Pin IAT sensor ISUZU TROOPER 1998 Service User Guide

6E±3 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0351
Ignition 1 Control Circuit 6E±206. . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P0352
Ignition 2 Control Circuit 6E±209. . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P0353
Ignition 3 Control Circuit 6E±212. . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P0354
Ignition 4 Control Circuit 6E±215. . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P0355
Ignition 5 Control Circuit 6E±218. . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P0356
Ignition 6 Control Circuit 6E±221. . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P0402
EGR Pintle Crank Error 6E±224. . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P0404
EGR Open Stuck 6E±226. . . . . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P0405
EGR Low Voltage 6E±228. . . . . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P0406
EGR High Voltage 6E±231. . . . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P0502
VSS Circuit Low Input 6E±234. . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P0562
System Voltage Low 6E±237. . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P0563
System Voltage High 6E±239. . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P0601
PCM Memory 6E±240. . . . . . . . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P1154
HO2S Circuit Transition Time Ratio Bank 2
Sensor 1 6E±241. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P1171
Fuel System Lean During Acceleration 6E±245. . . .
Diagnostic Trouble Code (DTC) P1380
ABS Rough Road ABS System Fault 6E±248. . . . . .
Diagnostic Trouble Code (DTC) P1404
EGR Closed Stuck 6E±249. . . . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P1508
IAC System Low RPM 6E±251. . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P1509
IAC System High RPM 6E±254. . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P1618
Serial Peripheral Interface (SPI) PCM
Interprocessor Communication Error 6E±257. . . . . .
Diagnostic Trouble Code (DTC) P1625
PCM Unexpected Reset 6E±258. . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P1640
Driver-1-Input High Voltage 6E±259. . . . . . . . . . . . . .
Symptom Diagnosis 6E±262. . . . . . . . . . . . . . . . . . . . .
Default Matrix Table 6E±288. . . . . . . . . . . . . . . . . . . . .
Camshaft Position (CMP) Sensor 6E±291. . . . . . . . . .
Crankshaft Position (CKP) Sensor 6E±292. . . . . . . . .
Engine Coolant Temperature (ECT) Sensor 6E±292.
Heated Oxygen Sensor (HO2S) 6E±293. . . . . . . . . . .
Intake Air Temperature (IAT) Sensor 6E±295. . . . . . .
Knock Sensor (KS) 6E±296. . . . . . . . . . . . . . . . . . . . . . Mass Air Flow (MAF) Sensor 6E±297. . . . . . . . . . . . .
Manifold Absolute Pressure (MAP) Sensor 6E±297.
Malfunction Indicator Lamp (MIL) 6E±298. . . . . . . . . .
Powertrain Control Module (PCM) 6E±298. . . . . . . . .
EEPROM 6E±300. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Steering Pressure (PSP) Switch 6E±300. . . .
Throttle Position (TP) Sensor 6E±301. . . . . . . . . . . . .
Vehicle Speed Sensor (VSS) 6E±302. . . . . . . . . . . . .
Air Cleaner/Air Filter 6E±303. . . . . . . . . . . . . . . . . . . . .
Idle Air Control (IAC) Valve 6E±304. . . . . . . . . . . . . . .
Common Chamber 6E±305. . . . . . . . . . . . . . . . . . . . . .
Accelerator Cable Assembly 6E±305. . . . . . . . . . . . . .
Accelerator Pedal Replacement 6E±308. . . . . . . . . . .
Fuel Filter Cap 6E±310. . . . . . . . . . . . . . . . . . . . . . . . . .
Fuel Filter 6E±310. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fuel Gauge Unit 6E±313. . . . . . . . . . . . . . . . . . . . . . . .
Fuel Injectors 6E±314. . . . . . . . . . . . . . . . . . . . . . . . . . .
Fuel Pressure Regulator 6E±315. . . . . . . . . . . . . . . . .
Fuel Metering System 6E±317. . . . . . . . . . . . . . . . . . . .
Fuel Pump Assembly 6E±318. . . . . . . . . . . . . . . . . . . .
Fuel Pump Relay 6E±319. . . . . . . . . . . . . . . . . . . . . . . .
Fuel Rail Assembly 6E±319. . . . . . . . . . . . . . . . . . . . . .
Fuel Tank 6E±321. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Throttle Body (TB) 6E±323. . . . . . . . . . . . . . . . . . . . . . .
Electronic Ignition System 6E±324. . . . . . . . . . . . . . . .
Catalytic Converter 6E±325. . . . . . . . . . . . . . . . . . . . . .
Air Conditioning Relay 6E±325. . . . . . . . . . . . . . . . . . .
EVAP Canister Hoses 6E±326. . . . . . . . . . . . . . . . . . . .
EVAP Canister 6E±326. . . . . . . . . . . . . . . . . . . . . . . . . .
EVAP Canister Purge Solenoid 6E±327. . . . . . . . . . . .
Fuel Tank Vent Valve 6E±328. . . . . . . . . . . . . . . . . . . .
Linear Exhaust Gas Recirculation
(EGR) Valve 6E±328. . . . . . . . . . . . . . . . . . . . . . . . . . .
Positive Crankcase Ventilation (PCV) Valve 6E±329.
Wiring and Connectors 6E±330. . . . . . . . . . . . . . . . . . .
PCM Connectors and Terminals 6E±330. . . . . . . . . . .
Wire Harness Repair: Twisted Shielded
Cable 6E±330. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Twisted Leads 6E±331. . . . . . . . . . . . . . . . . . . . . . . . . .
Weather-Pack Connector 6E±332. . . . . . . . . . . . . . . . .
Com-Pack III 6E±333. . . . . . . . . . . . . . . . . . . . . . . . . . .
Metri-Pack 6E±333. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
General Description 6E±335. . . . . . . . . . . . . . . . . . . . .
General Description (PCM and Sensors) 6E±335. . .
58X Reference PCM Input 6E±335. . . . . . . . . . . . . .
A/C Request Signal 6E±335. . . . . . . . . . . . . . . . . . . .
Crankshaft Position (CKP) Sensor 6E±335. . . . . . .
Camshaft Position (CMP) Sensor and
Signal 6E±335. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Engine Coolant Temperature (ECT) Sensor 6E±335
Electrically Erasable Programmable Read
Only Memory (EEPROM) 6E±336. . . . . . . . . . . . . .
Fuel Control Heated Oxygen Sensors 6E±336. . . .
Intake Air Temperature (IAT) Sensor 6E±336. . . . .

6E±17 ENGINE DRIVEABILITY AND EMISSIONS
PCM Pinouts
PCM Pinout Table, 32-Way Red Connector ± Row ªAº
TS23344
PINPIN FunctionWire ColorIGN ONENG RUNRefer To
A15 Volt Reference ªAºRED5.0 V5.0 VAppropriate Sensor
A2Knock SensorYEL0.0 V DC
2mV AC0.0 V DC
18mV AC
(at idle)General Description and
Operation, Knock Sensor
A3Not UsedÐÐÐÐ
A4Battery FeedWHTB+B+Chassis Electrical
A5Idle Air Control (IAC) ªAº
HighBLUB+/0.8 VB+/0.8 VGeneral Description and
Operation, IAC
A6IAC ªAº LowBLU/WHTB+/0.8 VB+/0.8 VGeneral Description and
Operation, IAC
A7IAC ªBº LowBLU/BLKB+/0.8 VB+/0.8 VGeneral Description and
Operation, IAC
A8IAC ªBº HighBLU/REDB+/0.8 VB+/0.8 VGeneral Description and
Operation, IAC
A9Automatic Transmission
Fluid (ATF) LampORN/BLUB+B+Automatic Transmission
(4L30E)
A10Winter LampPNK/GRNB+B+Automatic Transmission
(4L30E)
A11Power LampGRY/WHTB+B+Automatic Transmission
(4L30E)
A12Antilock Brake System
(ABS)GRYB+B+Antilock Brake System
A13Malfunction Indicator
(Check Engine or MIL)
LampBLU0.0 VB+Chassis Electrical
A14ªCheck Transmissionº
Lamp Driver (AT)ORN/BLKB+B+Chassis Electrical
Up Shift Lamp Driver (MT)ORN/BLU

6E±19 ENGINE DRIVEABILITY AND EMISSIONS
PCM Pinout Table, 32-Way Red Connector ± Row ªBº
TS23344
PINPIN FunctionWire ColorIGN ONENG RUNRefer To
B15 Volt Reference ªBºRED/YEL5.0 V5.0 VAppropriate Sensor
B2lgnition coilRED/WHT0.0 V0.1 VGeneral Description and
Operation
B3lgnition coilRED/BLK0.0 V0.1 VGeneral Description and
Operation
B4lgnition coilRED/GRN0.0 V0.1 VGeneral Description and
Operation
B5Not UsedÐÐÐÐ
B6Not UsedÐÐÐÐ
B7Exhaust Gas Recirculation
(EGR)YEL/RED0.6 V0.6 VGeneral Description and
Operation, Linear EGR
Control
B8Intake Air Temperature
(IAT) SensorYEL/GRN0.5-4.9 V
(depends on
temperature)0.5-4.9 V
(depends on
temperature)General Description and
Operation, IAT
B9Not UsedÐÐÐÐ
B10Not UsedÐÐÐÐ
B11Power Steering Pressure
(PSP) SwitchGRN/YELB+B+General Description and
Operation, PSP
B12Illuminated SwitchGRNB+B+Chassis Electrical
B13Class 2 DataORN/GRN0.0 V0.0 VDiagnosis, Class 2 Serial
Data
B14A/C ClutchGRN/BLKB+
(A/C OFF)B+
(A/C OFF)General Description and
Operation, A/C Clutch Circuit
Operation
B15ECM to ECU
CommunicationViolet0.0 V0.1 VÐ
B16Not UsedÐÐÐÐ

6E±22
ENGINE DRIVEABILITY AND EMISSIONS
PCM Pinout Table, 32-Way White Connector ± Row ªDº
(For except EXPORT and SOUTH AFRICA)
TS23345
PINPIN FunctionWire ColorIGN ONENG RUNRefer To
D1Injector Cylinder #2GRN/ORNB+B+General Description and
Operation, Fuel Injector
D2Torque Converter Clutch
(TCC)BRN/BLU0.0 V0.0 VOn-Vehicle Service, Torque
Converter Clutch
D3Injector Cylinder #1GRN/WHTB+B+General Description and
Operation, Fuel Injector
D4Serial Data (8192)ORN5.0 V5.0 VChassis Electrical
D5Ignition Control, Cylinder
#5RED/YEL0.0 V0.1 VGeneral Description and
Operation, Ignition Coil
D6Ignition Control, Cylinder
#3RED/BLUE0.0 V0.0 VGeneral Description and
Operation, Ignition Coil
D7VSS Input / IMOB
ResponseWHT/BLK0.0 V0.1 V
(at rest)Chassis Electrical
D8Sensor Ground 5V
Reference A ReturnGRN0.0 V0.0 VAppropriate Sensor
D9Sensor Ground 5 V
Reference B ReturnGRY0.0 V0.0 VAppropriate Sensor
D10Mass Air Flow (MAF)YEL4.9 V4.2 VGeneral Description, Mass
Air Flow Sensor
D11Camshaft Position SensorWHT5.0 V or less
than 1.0 V4.6 VGeneral Description and
Operation, Camshaft
Position Sensor
D12Not UsedÐÐÐÐ
D13Not UsedÐÐÐÐ
D14Bank 1 HO2S 1 LowGRN0.0 V0.1 VGeneral Description and
Operation, Fuel HO2S 1
D15Bank 1 HO2S 1 SignalRED0.4 V0.1-0.9 VGeneral Description and
Operation, Fuel HO2S 1
D16Not UsedÐÐÐÐ

6E±23 ENGINE DRIVEABILITY AND EMISSIONS
PCM Pinout Table, 32-Way White Connector ± Row ªDº
(For EXPORT and SOUTH AFRICA)
TS23345
PINPIN FunctionWire ColorIGN ONENG RUNRefer To
D1Injector Cylinder #2GRN/ORNB+B+General Description and
Operation, Fuel Injector
D2Torque Converter Clutch
(TCC)BRN/BLU0.0 V0.0 VOn-Vehicle Service, Torque
Converter Clutch
D3Injector Cylinder #1GRN/WHTB+B+General Description and
Operation, Fuel Injector
D4Serial Data (8192)ORN5.0 V5.0 VChassis Electrical
D5Ignition Control, Cylinder
#5RED/YEL0.0 V0.1 VGeneral Description and
Operation, Ignition Coil
D6Ignition Control, Cylinder
#3RED/BLUE0.0 V0.0 VGeneral Description and
Operation, Ignition Coil
D7VSS Input / IMOB
ResponseLIGHT
GRN/WHT0.0 V0.1 V
(at rest)Chassis Electrical
D8Sensor Ground 5V
Reference A ReturnGRN0.0 V0.0 VAppropriate Sensor
D9Sensor Ground 5 V
Reference B ReturnGRY0.0 V0.0 VAppropriate Sensor
D10Mass Air Flow (MAF)YEL4.9 V4.2 VGeneral Description, Mass
Air Flow Sensor
D11Camshaft Position SensorWHT5.0 V or less
than 1.0 V4.6 VGeneral Description and
Operation, Camshaft
Position Sensor
D12Not UsedÐÐÐÐ
D13Not UsedÐÐÐÐ
D14Not UsedÐÐÐÐ
D15Not UsedÐÐÐÐ
D16Not UsedÐÐÐÐ

6E±38
ENGINE DRIVEABILITY AND EMISSIONS
General Service Information
OBD Serviceablity Issues
The list of non-vehicle faults that could affect the
performance of the OBD system has been compiled.
These non-vehicle faults vary from environmental
conditions to the quality of fuel used.
The illumination of the MIL (ªCheck Engineº lamp) due to
a non-vehicle fault could lead to misdiagnosis of the
vehicle, increased warranty expense and customer
dissatisfaction. The following list of non-vehicle faults
does not include every possible fault and may not apply
equally to all product lines.
Fuel Quality
Using fuel with the wrong octane rating for your vehicle
may cause driveability problems. Many of the major fuel
companies advertise that using ªpremiumº gasoline will
improve the performance of your vehicle. Most premium
fuels use alcohol to increase the octane rating of the fuel.
Although alcohol-enhanced fuels may raise the octane
rating, the fuel's ability to turn into vapor in cold
temperatures deteriorates. This may affect the starting
ability and cold driveability of the engine.
Low fuel levels can lead to fuel starvation, lean engine
operation, and eventually engine misfire.
Non-OEM Parts
All of the OBD diagnostics have been calibrated to run
with OEM parts. Something as simple as a
high-performance exhaust system that affects exhaust
system back pressure could potentially interfere with the
operation of the EGR valve and thereby turn on the MIL
(ªCheck Engineº lamp). Small leaks in the exhaust
system near the post catalyst oxygen sensor can also
cause the MIL (ªCheck Engineº lamp) to turn on.
Aftermarket electronics, such as cellular phones,
stereos, and anti-theft devices, may radiate EMI into the
control system if they are improperly installed. This may
cause a false sensor reading and turn on the MIL (ªCheck
Engineº lamp).
Environment
Temporary environmental conditions, such as localized
flooding, will have an effect on the vehicle ignition system.
If the ignition system is rain-soaked, it can temporarily
cause engine misfire and turn on the MIL (ªCheck Engineº
lamp).
Poor Vehicle Maintenance
The sensitivity of OBD diagnostics will cause the MIL
(ªCheck Engineº lamp) to turn on if the vehicle is not
maintained properly. Restricted air filters, fuel filters, and
crankcase deposits due to lack of oil changes or improper
oil viscosity can trigger actual vehicle faults that were not
previously monitored prior to OBD. Poor vehicle
maintenance can not be classified as a ªnon-vehicle
faultº, but with the sensitivity of OBD diagnostics, vehicle
maintenance schedules must be more closely followed.Related System Faults
Many of the OBD system diagnostics will not run if the
PCM detects a fault on a related system or component.
One example would be that if the PCM detected a Misfire
fault, the diagnostics on the catalytic converter would be
suspended until Misfire fault was repaired. If the Misfire
fault was severe enough, the catalytic converter could be
damaged due to overheating and would never set a
Catalyst DTC until the Misfire fault was repaired and the
Catalyst diagnostic was allowed to run to completion. If
this happens, the customer may have to make two trips to
the dealership in order to repair the vehicle.
Maintenance Schedule
Refer to the Maintenance Schedule.
Visual / Physical Engine Compartment
Inspection
Perform a careful visual and physical engine
compartment inspection when performing any diagnostic
procedure or diagnosing the cause of an emission test
failure. This can often lead to repairing a problem without
further steps. Use the following guidelines when
performing a visual/physical inspection:

Inspect all vacuum hoses for punches, cuts,
disconnects, and correct routing.

Inspect hoses that are difficult to see behind other
components.

Inspect all wires in the engine compartment for proper
connections, burned or chafed spots, pinched wires,
contact with sharp edges or contact with hot exhaust
manifolds or pipes.
Basic Knowledge of Tools Required
NOTE: Lack of basic knowledge of this powertrain when
performing diagnostic procedures could result in an
incorrect diagnosis or damage to powertrain
components. Do not attempt to diagnose a powertrain
problem without this basic knowledge.
A basic understanding of hand tools is necessary to effec-
tively use this section of the Service Manual.
Serial Data Communications
Class II Serial Data Communications
This vehicle utilizes the ªClass IIº communication system.
Each bit of information can have one of two lengths: long
or short. This allows vehicle wiring to be reduced by
transmitting and receiving multiple signals over a single
wire. The messages carried on Class II data streams are
also prioritized. If two messages attempt to establish
communications on the data line at the same time, only
the message with higher priority will continue. The device
with the lower priority message must wait. The most
significant result of this regulation is that it provides Tech 2
manufacturers with the capability to access data from any
make or model vehicle that is sold.

6E±65 ENGINE DRIVEABILITY AND EMISSIONS
Knock Sensor Diagnosis
The Tech 2 has two data displays available for diagnosing
the knock sensor (KS) system. The two displays are
described as follows:

ªKnock Retardº indicates the number of degrees that
the spark timing is being retarded due to a knock
condition.

ªKS Noise Channelº indicates the current voltage level
being monitored on the noise channel.
DTCs P0325 and P0327 are designed to diagnose the KS
module, the knock sensor, and the related wiring. The
problems encountered with the KS system should set a
DTC. However, if no DTC was set but the KS system is
suspect because of a detonation complaint, refer to
Detonation/Spark Knock in Symptoms.
Powertrain Control Module (PCM)
Diagnosis
To read and clear diagnostic trouble codes, use a Tech 2.
IMPORTANT:Use of a Tech 2 is recommended to clear
diagnostic trouble codes from the PCM memory.
Diagnostic trouble codes can also be cleared by turning
the ignition ªOFFº and disconnecting the battery power
from the PCM for 30 seconds. Turning off the ignition and
disconnecting the battery power from the PCM will cause
all diagnostic information in the PCM memory to be
cleared. Therefore, all the diagnostic tests will have to be
re-run.
Since the PCM can have a failure which may affect only
one circuit, following the diagnostic procedures in this
section will determine which circuit has a problem and
where it is.
If a diagnostic chart indicates that the PCM connections
or the PCM is the cause of a problem, and the PCM is
replaced, but this does not correct the problem, one of the
following may be the reason:

There is a problem with the PCM terminal connections.
The terminals may have to be removed from the
connector in order to check them properly.

The problem is intermittent. This means that the
problem is not present at the time the system is being
checked. In this case, refer to the
Symptoms portion of
the manual and make a careful physical inspection of
all component and wiring associated with the affected
system.

There is a shorted solenoid, relay coil, or harness.
Solenoids and relays are turned ªONº and ªOFFº by the
PCM using internal electronic switches called drivers.
A shorted solenoid, relay coil, or harness will not
damage the PCM but will cause the solenoid or relay to
be inoperative.
Multiple PCM Information Sensor
DTCS Set
Circuit Description
The powertrain control module (PCM) monitors various
sensors to determine the engine operating conditions.
The PCM controls fuel delivery, spark advance,
transmission operation, and emission control device
operation based on the sensor inputs.The PCM provides a sensor ground to all of the sensors.
The PCM applies 5 volts through a pull-up resistor, and
determines the status of the following sensors by
monitoring the voltage present between the 5-volt supply
and the resistor:

The engine coolant temperature (ETC) sensor

The intake air temperature (IAT) sensor

The transmission fluid temperature (TFT) sensor
The PCM provides the following sensors with a 5-volt
reference and a sensor ground signal:

The exhaust gas recirculating (EGR) pintle position
sensor

The throttle position (TP) sensor

The manifold absolute pressure (MAP) sensor
The PCM monitors the separate feedback signals from
these sensors in order to determine their operating
status.
Diagnostic Aids
IMPORTANT:Be sure to inspect PCM and engine
grounds for being secure and clean.
A short to voltage in one of the sensor input circuits may
cause one or more of the following DTCs to be set:

P0108

P0113

P0118

P0123

P0560

P0712

P0406
IMPORTANT:If a sensor input circuit has been shorted
to voltage, ensure that the sensor is not damaged. A
damaged sensor will continue to indicate a high or low
voltage after the affected circuit has been repaired. If the
sensor has been damaged, replace it.
An open in the sensor ground circuit between the PCM
and the splice will cause one or more of the following
DTCs to be set:

P0108

P0113

P0118

P0123

P0712

P0406
A short to ground in the 5-volt reference A or B circuit will
cause one or more of the following DTCs to be set:

P0107

P0122
In the 5-volt reference circuit A, between the PCM and the
splice, will cause one or more of the following DTCs to be
set:

P0122
In the 5-volt reference circuit B, between the PCM and the
splice, will cause one or more of the following DTCs to be
set:

P0107
Check for the following conditions:

6E±66
ENGINE DRIVEABILITY AND EMISSIONS

Poor connection at PCM. Inspect the harness
connectors for backed-out terminals, improper mating,
broken locks, improperly formed or damage terminals,
and a poor terminal-to-wire connection.

Damaged harness. Inspect the wiring harness for
damage. If the harness is not damaged, observe an
affected sensor's displayed value on the Tech 2 with
the ignition ªONº and the engine ªOFFº while you move
the connectors and the wiring harnesses related to the
following sensors:
IAT

ECT

TP

MAP

EGR

TFT
Multiple PCM Information Sensor DTCs Set

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Turn the ignition ªOFF,º disconnect the PCM.
2. Turn the ignition ªON,º check the 5 volt reference A
circuit for the following conditions:

A poor connection at the PCM.

An open between the PCM connector and the
splice.

A short to ground.

A short to voltage.
Is there an open or short?
ÐGo to Step 3Go to Step 4
3Repair the open or short.
Is the action complete?
ÐVerify repairÐ
4Check the sensor ground circuit for the following
conditions:

A poor connection at the PCM or the affected
sensors.

An open between the PCM connector and the
affected sensors.
Is there an open or a poor connection?
ÐGo to Step 5Go to Step 6
5Repair the open or the poor connection.
Is the action complete?
ÐVerify repairÐ
6Measure the voltage between the EGR pintle position
sensor signal circuit at the PCM harness connector and
ground.
Does the voltage measure near the specified value?
0 VGo to Step 7Go to Step 12
7Measure the voltage between the MAP sensor signal
circuit at the PCM harness connector and ground.
Does the voltage measure near the specified value?
0 VGo to Step 8Go to Step 15
8Measure the voltage between the TP sensor signal
circuit at the PCM harness connector and ground.
Does the voltage measure near the specified value?
0 VGo to Step 9Go to Step 16
9Measure the voltage between the IAT sensor signal
circuit at the PCM harness connector and ground.
Does the voltage measure near the specified value?
0 VGo to Step 10Go to Step 17
10Measure the voltage between the ECT sensor signal
circuit at the PCM harness connector and ground.
Does the voltage measure near the specified value?
0 VGo to Step 11Go to Step 18

6E±67 ENGINE DRIVEABILITY AND EMISSIONS
Multiple PCM Information Sensor DTCs Set

 
StepNo Ye s Value(s) Action
111. Disconnect the EGR valve.
2. Measure the voltage between the EGR pintle
position sensor signal circuit at the PCM harness
connector and ground.
Does the voltage measure near the specified value?
0 VGo to Step 13Go to Step 18
12Measure the voltage between the TFT sensor signal
circuit at the PCM harness connector and ground.
Does the voltage measure near the specified value?
0 VGo to Step 20Go to Step 19
13Replace the EGR valve.
Is the action complete?
ÐVerify repairÐ
14Locate and repair the short to voltage in the MAP
sensor signal circuit.
Is the action complete?
ÐVerify repairÐ
15Locate and repair the short to voltage in the TP sensor
signal circuit.
Is the action complete?
ÐVerify repairÐ
16Locate and repair the short to voltage in the IAT sensor
signal circuit.
Is the action complete?
ÐVerify repairÐ
17Locate and repair the short to voltage in the ECT
sensor signal circuit.
Is the action complete?
ÐVerify repairÐ
18Locate and repair the short to voltage in the EGR pintle
position sensor signal circuit.
Is the action complete?
ÐVerify repairÐ
19Locate and repair the short to voltage in the TFT sensor
signal circuit.
Is the action complete?
ÐVerify repairÐ
20Replace the PCM.
IMPORTANT:The replacement PCM must be
programmed. Refer to
UBS 98model year Immobilizer
Workshop Manual.
Is the action complete?Ð
Go to OBD
System
Check
Ð

6E±68
ENGINE DRIVEABILITY AND EMISSIONS
Exhaust Gas Recirculation (EGR)
Diagnosis (For except EXPORT and
SOUTH AFRICA)
Pintle position error diagnosis is covered by DTC P0402,
P0404, P1404, P0405, P0406. If EGR diagnostic trouble
codes P0402, P0404, P1404, P0405, P0406 are
encountered, refer to the DTC charts.
Engine Tech 2 Data Definitions and
Ranges
A/C CLUTCH ± Tech 2 Displays ON or OFF ±
Indicates whether the PCM has commanded the A/C
clutch ON. Used in A/C system diagnostic.
A/C REQUEST Ð Tech 2 Displays YES or NO Ð
Indicates the state of the A/C request input circuit from the
HVAC controls. The PCM uses the A/C request signal to
determine whether A/C compressor operation is being
requested.
AIR/FUEL RATIO Ð Tech 2 Range 0.0-25.5 Ð
Air/fuel ratio indicates the PCM commanded value. In
closed loop, the air/fuel ratio should normally be
displayed around ª14.2-14.7.º A lower air/fuel ratio
indicates a richer commanded mixture, which may be
seen during power enrichment or TWC protection modes.
A higher air/fuel ratio indicates a leaner commanded
mixture. This can be seen during deceleration fuel mode.
BAROMETRIC PRESSURE Ð Tech 2 Range 10-105
kPa/0.00-5.00 Volts Ð
The barometric pressure reading is determined from the
MAP sensor signal monitored during key up and wide
open throttle (WOT) conditions. The barometric pressure
is used to compensate for altitude differences and is
normally displayed around ª61-104º depending on
altitude and barometric pressure.
CHECK TRANS LAMP Ð AUTO TRANSMISSION Ð
Indicates the need to check for a DTC with the Tech 2
when the lamp is flashing 0.2 seconds ON and 0.2
seconds OFF.
CMP ACT. COUNTER ± Cam Position Activity
DECEL FUEL MODE Ð Tech 2 Display ACTIVE or
INACTIVE Ð
ªACTIVEº displayed indicates that the PCM has detected
conditions appropriate to operate in deceleration fuel
mode. The PCM will command the deceleration fuel
mode when it detects a closed throttle position while the
vehicle is traveling over 20 mph. While in the deceleration
fuel delivered by entering open loop and decreasing the
injector pulse width.
DESIRED EGR POS. Ð Tech 2 Range 0%-100% Ð
Represents the EGR pintle position that the PCM is
commanding.
DESIRED IDLE Ð Tech 2 Range 0-3187 RPM Ð
The idle speed that the PCM is commanding. The PCM
will compensate for various engine loads based on engine
coolant temperature, to keep the engine at the desired
speed.ECT Ð (Engine Coolant Temperature) Tech 2
Range ±40
C to 151
C (±40
F to 304
F) Ð
The engine coolant temperature (ECT) is mounted in the
coolant stream and sends engine temperature
information to the PCM. The PCM applies 5 volts to the
ECT sensor circuit. The sensor is a thermistor which
changes internal resistance as temperature changes.
When the sensor is cold (high resistance), the PCM
monitors a high signal voltage and interprets that as a cold
engine. As the sensor warms (decreasing resistance),
the voltage signal will decrease and the PCM will interpret
the lower voltage as a warm engine.
EGR DUTY CYCLE Ð Tech 2 Range 0%-100% Ð
Represents the EGR valve driver PWM signal from the
PCM. A duty cycle of 0% indicates that no EGR flow is
being commanded; a 100% duty cycle indicates
maximum EGR flow commanded.
EGR FEEDBACK Ð Tech 2 Range 0.00-5.00 Volts Ð
Indicates the EGR pintle position sensor signal voltage
being monitored by the PCM. A low voltage indicates a
fully extended pintle (closed valve); a voltage near 5 volts
indicates a retracted pintle (open valve).
ENGINE LOAD Ð Tech 2 Range 0%-100% Ð
Engine load is calculated by the PCM from engine speed
and MAF sensor readings. Engine load should increase
with an increase in RPM or air flow.
ENGINE RUN TIME Ð Tech 2 Range
00:00:00-99:99:99 Hrs:Min:Sec Ð
Indicates the time elapsed since the engine was started.
If the engine is stopped, engine run time will be reset to
00:00:00.
ENGINE SPEED Ð Range 0-9999 RPM Ð
Engine speed is computed by the PCM from the 58X
reference input. It should remain close to desired idle
under various engine loads with engine idling.
FUEL PUMP Ð Tech 2 Displays ON or OFF Ð
Indicates the PCM commanded state of the fuel pump
relay driver circuit.
FUEL TRIM CELL Ð Tech 2 Range 0-21 Ð
The fuel trim cell is dependent upon engine speed and
MAF sensor readings. A plot of RPM vs. MAF is divided
into 22 cells. Fuel trim cell indicates which cell is currently
active.
FUEL TRIM LEARN Ð Tech 2 Displays NO or YES
Ð
When conditions are appropriate for enabling long term
fuel trim corrections, fuel trim learn will display ªYES.º
This indicates that the long term fuel trim is responding to
the short term fuel trim. If the fuel trim learn displays
ªNO,º then long term fuel trim will not respond to changes
in short term fuel trim.
HO2S BANK 1, SEN. 1 Ð Tech 2 Range 0-1132 mV
Ð
Represents the fuel control exhaust oxygen sensor
output voltage. Should fluctuate constantly within a range
between 10 mV (lean exhaust) and 1000 mV (rich
exhaust) while operating in closed loop.