ignition CHRYSLER VOYAGER 2001 Service Manual

3.2.2 ECM OPERATING MODES
As input signals to the ECM change, the ECM
adjusts its response to the output devices. For
example, the ECM must calculate a different fuel
quantity and fuel timing for engine idle condition
than it would for a wide open throttle condition.
There are several different modes of operation that
determine how the ECM responds to the various
input signals.
Ignition Switch On (Engine Off)
When the ignition switch is turned on, the ECM
activates the glow plug relay for a time period that
is determined by engine coolant temperature, atmo-
spheric temperature and battery voltage. The ECM
also activates the lift pump to prime the fuel sys-
tem.
Engine Start-up Mode
The ECM uses the engine temperature sensor
and the crankshaft position sensor (engine speed)
inputs to determine fuel injection quantity.
Normal Driving Modes
Engine idle, warm-up, acceleration, deceleration
and wide open throttle modes are controlled based
on all of the sensor inputs to the ECM. The ECM
uses these sensor inputs to adjust fuel quantity and
fuel injector timing.
Overheat Protection Mode
If engine temperature is above 106É C (223É F)
and vehicle speed is above 40 km/h (25 MPH) the
ECM will activate the high speed fan and will limit
fuel quantity for engine protection.
Limp-In Mode
If there is a fault detected with the accelerator
pedal position sensor, the ECM will set the engine
speed at 1100 RPM.
Overspeed Detection Mode
If the ECM detects engine RPM that exceeds
5000 RPM, the ECM will set a DTC in memory and
limit engine RPM to no more that 2500 RPM until
the DTC(s) is cleared.
After-Run Mode
The ECM transfers RAM information to ROM
and performs an Input/Output state check.
3.2.3 MONITORED CIRCUITS
The ECM is able to monitor and identify most
driveability related trouble conditions. Some cir-
cuits are directly monitored through ECM feedback
circuitry. In addition, the ECM monitors the voltage
state of some circuits and compares those stateswith expected values. Other systems are monitored
indirectly when the ECM conducts a rationality test
to identify problems.
Although most subsystems of the engine control
module are either directly or indirectly monitored,
there may be occasions when diagnostic trouble
codes are not immediately identified. For a trouble
code to set, a specific set of conditions must occur
and unless these conditions occur, a DTC will not
set.
3.2.4 SKIS OVERIVEW
The sentry key immobilizer system (SKIS) is
designed to prevent unauthorized vehicle opera-
tion. The system consists of a sentry key immobi-
lizer module (SKIM), ignition key(s) equipped with
a transponder chip and the ECM. When the ignition
switch is turned on, the SKIM interrogates the
ignition key. If the ignition key is Valid or Invalid,
the SKIM sends a PCI Bus message to the ECM
indicating ignition key status. Upon receiving this
message the ECM will terminate engine operation
or allow the engine to continue to operate.
3.2.5 SKIS ON-BOARD DIAGNOSTICS
The sentry key immobilizer module (SKIM) has
been programmed to transmit and monitor many
different coded messages as well as PCI Bus mes-
sages. This monitoring is called On-Board Diagnos-
tics. Certain criteria must be met for a DTC to be
entered into SKIM memory. The criteria may be a
range of; input voltage, PCI Bus message or coded
messages to the SKIM. If all of the criteria for
monitoring a circuit or function are met and a fault
is detected, a DTC will be stored in the SKIM
memory.
3.2.6 SKIS OPERATION
When ignition power is supplied to the SKIM, the
SKIM performs an internal self-test. After the self-
test is complete, the SKIM energizes the antenna
(this activates the transponder chip) and sends a
challenge to the transponder chip. The transponder
chip responds to the challenge by generating an
encrypted response message using the following:
Secret Key - This is an electronically stored value
(identification number) that is unique to each SKIS.
The secret key is stored in the SKIM, ECM and all
ignition key transponders.
Challenge - This is a random number that is gen-
erated by the SKIM at each ignition key cycle.
The secret key and challenge are the two vari-
ables used in the algorithm that produces the
encrypted response message. The transponder uses
the crypto algorithm to receive, decode and respond
to the message sent by SKIM. After responding to
the coded message, the transponder sends a tran-
2
GENERAL INFORMATION

sponder ID message to the SKIM. The SKIM com-
pares the transponder ID message to the available
valid key codes in SKIM memory (8 key maximum
at any one time). After validating the ignition key,
the SKIM sends a PCI Bus message called a seed
request to the ECM, then waits for the ECM re-
sponse. If the ECM does not respond, the SKIM will
send the seed request again. After three failed
attempts, the SKIM will stop sending the seed
request and store a trouble code in memory. If the
ECM sends a seed response, the SKIM sends a
valid/invalid key message to the ECM. This is an
encrypted message that is generated using the
following:
VIN - Vehicle Identification Number.
Seed - This is a random number that is generated
by the ECM at each ignition key cycle.
The VIN and seed are two variables used in the
rolling code algorithm that encrypts the valid/
invalid key message. The ECM uses the rolling code
algorithm to receive, decode and respond to the
valid/invalid key message sent by the SKIM. After
sending the valid/invalid key message, the SKIM
waits 3.5 seconds for an ECM status message from
the ECM. If the ECM does not respond with a valid
key message to the SKIM, a fault is detected and a
code is stored.
The SKIS incorporates a warning lamp located in
the information center. The lamp receives switched
ignition voltage and is hardwired to the body con-
trol module. The lamp is actuated when the SKIM
sends a PCI Bus message to the body control
module requesting the lamp on. The body control
module then provides the ground for the lamp.
The SKIM will request lamp operation for the
following:
± bulb check at ignition on
± to alert the vehicle operator to a SKIS malfunc-
tion
± when the SKIM is in customer key programming
mode
For all faults except transponder faults the lamp
remains on steady. In the event of a transponder
fault the lamp will flash at a rate of 1Hz (once per
second). If a fault is present, the lamp will remain
on or flashing for the complete ignition cycle. If a
fault is stored in SKIM memory which prevents the
system from operating properly, the ECM will allow
the engine to start and idle for 2 seconds then stall.
This may occur up to six times. After the sixth
attempt, the ECM disables the starter relay until
the fault is corrected.
3.3 DIAGNOSTIC TROUBLE CODES
Each diagnostic trouble code (DTC) is diagnosed
by following a specific procedure. The diagnostic
test procedure contains step-by-step instruction fordetermining the cause of the DTC as well as no
trouble code problems. It is not necessary to per-
form all of the tests in this book to diagnose an
individual code.
Always begin diagnosis by reading the DTC's
using the DRBIIIt.
3.3.1 HARD CODE
A DTC that comes back within one cycle of the
ignition key is a hard code. This means that the
problem is current every time the ECM/SKIM
checks that circuit or function. Procedures in this
manual verify if the DTC is a hard code at the
beginning of each test. When the fault is not a hard
code, an intermittent test must be performed.
NOTE: If the DRBIIItdisplays faults for multiple
components (i.e. ECT, VSS, Oil Temp sensors) iden-
tify and check the shared circuits for possible prob-
lems before continuing (i.e. sensor grounds or 5-volt
supply circuits). Refer to the appropriate schematic
to identify shared circuits.
3.3.2 INTERMITTENT CODE
A DTC that is not current every time the ECM/
SKIM checks the circuit or function is an intermit-
tent code. Most intermittent DTCs are caused by
wiring or connector problems. Problems that come
and go like this are the most difficult to diagnose;
they must be looked for under specific conditions
that cause them. The following checks may assist
you in identifying a possible intermittent problem.
²Visually inspect the related wire harness connec-
tors. Look for broken, bent, pushed out, or cor-
roded terminals.
²Visually inspect the related wire harness. Look
for chafed, pierced, or partially broken wire.
²Refer to hotlines or technical service bulletins
that may apply.
NOTE: Electromagnetic (radio) interference can
cause an intermittent system malfunction. This
interference can interrupt communication between
the ignition key transponder and the SKIM.
3.3.3 ECM DIAGNOSTIC TROUBLE CODES
IMPORTANT NOTE:Before replacing the ECM
for a failed driver, control circuit or ground circuit,
be sure to check the related component/circuit in-
tegrity for failures not detected due to a double fault
in the circuit. Most ECM driver/control circuit fail-
ures are caused by internal failures to components
(i.e. relays and solenoids) and shorted circuits (i.e.
sensor pull-ups, drivers and ground circuits). These
faults are difficult to detect when a double fault has
occurred and only one DTC has set.
If the DRB displays faults for multiple compo-
nents (i.e. VSS, ECT, Batt Temp, etc.), identify and
3
GENERAL INFORMATION

A/C PRESSURE SENSOR CIRCUIT SIGNAL
VOLTAGE TOO HIGH
A/C PRESSURE SENSOR CIRCUIT SIGNAL
VOLTAGE TOO LOW
A/C PRESSURE SENSOR CIRCUIT SUPPLY
VOLTAGE TOO HIGH OR LOW
A/C PRESSURE SENSOR CIRCUIT PLAUSI-
BILITY
SYSTEM VOLTAGE TOO HIGH
SYSTEM VOLTAGE TOO LOW
S/C SWITCH SIGNAL CIRCUIT SIGNAL VOLT-
AGE TOO HIGH
S/C SWITCH SIGNAL CIRCUIT SIGNAL VOLT-
AGE TOO LOW
S/C SWITCH SIGNAL CIRCUIT PLAUSIBILITY
ECM ERROR RECOVERY HAS OCCURRED
ECM ERROR REDUNDANT OVERRUN MONI-
TORING
ECM ERROR GATE ARRAY - QUANTITY STOP
ECM ERROR GATE ARRAY - COMMUNICA-
TION
ECM ERROR - COMMUNICATION NOT VERI-
FIED
STARTER RELAY CIRCUIT OPEN CIRCUIT
STARTER RELAY CIRCUIT SHORT CIRCUIT
GENERATOR FIELD CONTROL MALF BAT-
TERY VOLTAGE TOO HIGH
GENERATOR FIELD CONTROL MALF BAT-
TERY VOLTAGE TOO LOW
GENERATOR FIELD CONTROL MALF OPEN
CIRCUIT
GENERATOR FIELD CONTROL MALF SHORT
CIRCUIT
GENERATOR FIELD CONTROL MALF
CHARGING VOLTS TOO LOW
GENERATOR FIELD CONTROL MALF BAT-
TERY VOLTAGE DEVIATION TOO HIGH
GENERATOR FIELD CONTROL MALF BAT-
TERY VOLTAGE DEVIATION TOO LOW
GENERATOR FIELD CONTROL MALF UN-
STABLE CURRENT
SENSOR REFERENCE VOLTAGE A CKT VOLT-
AGE TOO HIGH
SENSOR REFERENCE VOLTAGE A CKT VOLT-
AGE TOO LOW
SENSOR REFERENCE VOLTAGE B CKT
VOLTAGE TOO HIGH
SENSOR REFERENCE VOLTAGE B CKT
VOLTAGE TOO LOW
A/C CLUTCH RELAY CIRCUIT OPEN CIRCUIT
A/C CLUTCH RELAY CIRCUIT SHORT CIR-
CUIT
ECM/PCM RELAY CONTROL CIRCUIT SHUTS
OFF TOO EARLY
ECM/PCM RELAY CONTROL CIRCUIT SHUTS
OFF TOO LATE
BRAKE SWITCH SIGNAL CIRCUITS INCOR-
RECT CAN MESSAGEBRAKE SWITCH SIGNAL CIRCUITS PLAUSI-
BILITY WITH REDUNDANT CONTACT
BRAKE SWITCH SIGNAL CIRCUITS PLAUSI-
BILITY WITH REDUNDANT CONTACT AFTER
INITIALIZATION
CLUTCH UPSTOP SWITCH PERF PLAUSIBIL-
ITY
CLUTCH UPSTOP SWITCH PERF PLAUSIBIL-
ITY WITH P/N SWITCH
FUEL RAIL PRESSURE MALFUNCTION
PRESSURE TOO HIGH - LIMITATION
FUEL RAIL PRESSURE MALFUNCTION
PRESSURE TOO LOW
FUEL RAIL PRESSURE MALFUNCTION SO-
LENOID OPEN
FUEL RAIL PRESSURE MALFUNCTION
LEAKAGE DETECTED
FUEL PRESSURE SOLENOID OPEN CIRCUIT
FUEL PRESSURE SOLENOID SHORT CIR-
CUIT
FUEL PRESSURE SOLENOID PLAUSIBILITY
IN AFTER-RUN
CALCULATED INJECTOR VOLTAGE - VOLT-
AGE 1 TOO LOW
CALCULATED INJECTOR VOLTAGE - VOLT-
AGE 2 TOO LOW
BATTERY SENSE LINE 1 VOLTAGE TOO
HIGH
BATTERY SENSE LINE 1 VOLTAGE TOO LOW
FUEL PRESS REG CURRENT CONTROL SIG-
NAL TOO HIGH
FUEL PRESS REG CURRENT CONTROL SIG-
NAL TOO LOW
GENERATOR FIELD CURRENT TOO HIGH
GENERATOR FIELD CURRENT TOO LOW
CAPACITOR VOLTAGE 1 VOLTAGE TOO HIGH
CAPACITOR VOLTAGE 1 VOLTAGE TOO LOW
CAPACITOR VOLTAGE 2 VOLTAGE TOO HIGH
CAPACITOR VOLTAGE 2 VOLTAGE TOO LOW
IGNITION SWITCH PLAUSIBILITY
AFTER RUN SHUT OFF ERROR - ZERO
QUANTITY
AFTERRUN SHUT OFF ERROR - INJ. POWER-
STAGE
VOLTAGE REGULATOR SIGNAL VOLTAGE
TOO HIGH
VOLTAGE REGULATOR SIGNAL VOLTAGE
TOO LOW
MIL/DIAG LAMP VIA J1850 BUS IN FRAME
RESPONSE ERROR
MIL/DIAG LAMP VIA J1850 BUS - STATUS
ERROR
J1850 COMMUNICATION BUS SHORT TO
VOLTAGE
J1850 COMMUNICATION BUS SHORT TO
GROUND
J1850 COMMUNICATION BUS TRANSMIT
BUFFER OVERRUN
5
GENERAL INFORMATION

4.3 WARNINGS AND CAUTIONS
4.3.1 ROAD TEST WARNINGS
Some complaints will require a test drive as part
of the repair verification procedure. The purpose of
the test drive is to try to duplicate the diagnostic
code or symptom condition.
CAUTION: BEFORE ROAD TESTING A
VEHICLE, BE SURE THAT ALL
COMPONENTS ARE REASSEMBLED. DUR-
ING THE TEST DRIVE, DO NOT HANG THE
DRBIIITFROM THE REAR VIEW MIRROR. DO
NOT ATTEMPT TO READ THE DRBIIITWHILE
DRIVING. HAVE AN ASSISTANT AVAILABLE
TO OPERATE THE DRBIIIT.
4.3.2 VEHICLE DAMAGE CAUTIONS
Before disconnecting any control module, make
sure the ignition is off. Failure to do so could
damage the module. When testing voltage or circuit
integrity at any control module, use the terminal
side (not the wire end) of the harness connector. Do
not probe through the insulation; this will damage
it and eventually cause it to fail because of corro-
sion.
Be careful when performing electrical test so as to
prevent accidental shorting of terminals. Such a
mistake can damage fuses or components. Also, a
second code could be set, making diagnosis of the
original problem more difficult.
5.0 REQUIRED TOOLS AND
EQUIPMENT
DRBIIIt(diagnostic read-out box) scan tool
vacuum gauge
ammeter
ohmmeter
jumper wires and probes
oscilloscope
6.0 GLOSSARY OF TERMS
A/Cair conditioning
APPaccelerator pedal position (sensor)
backfire,
popbackfuel ignites in either the intake or
the exhaust system
BCMbody control module
BPboost pressure (sensor)CKPcrankshaft position (sensor)
CMPcamshaft position (sensor)
cuts out,
missesa steady pulsation or the inability of
the engine to maintain a consistent
rpm
DLCdata link connector
detona-
tion,
spark
knocka mild to severe ping, especially un-
der loaded engine conditions
ECMengine control module
ECTengine coolant temperature (sensor)
EGRexhaust gas recirculation
(solenoid/valve)
hard
startthe engine takes longer than usual
to start, even though it is able to
crank at normal speed.
IATintake air temperature (sensor)
IPMintelligent power module
lack of
power,
sluggishthe engine power output has been
reduced
MAFmass air flow (sensor)
MILmalfunction indicator lamp
msmillisecond(s)
PDCpower distribution center
poor fuel
economythere is significantly less fuel mile-
age than other vehicles of the same
design and configuration
runs
rough/
unstable
idlethe engine runs unevenly at idle
causing the engine to shake if it is
severe enough
S/Cspeed control
SKIMsentry key immobilizer module
SKISsentry key immobilizer system
start and
stallThe engine starts but immediately
dies (stalls)
surgeengine rpm fluctuation without cor-
responding change in accelerator
pedal position
SRCsignal range check
WIFwater in fuel (sensor)
VSSvehicle speed sensor
8
GENERAL INFORMATION

Symptom:
*NO RESPONSE FROM ECM (PCI BUS) - DIESEL ONLY
POSSIBLE CAUSES
ECM PCI NO RESPONSE
PCI BUS CIRCUIT OPEN
ENGINE CONTROL MODULE
TEST ACTION APPLICABILITY
1 Turn the ignition on.
NOTE: As soon as one or more module communicates with the DRB, answer
the question.
With the DRB, enter Body then Body Computer.
With the DRB, enter Anti-Lock Brakes.
With the DRB, enter Body then Electro/Mechanical Cluster (MIC).
With the DRB, enter Passive Restraints then Airbag.
Were you able to establish communications with any of the modules?All
Ye s®Go To 2
No®Refer to symptom PCI Bus Communication Failure in the Com-
munications category.
Perform ROAD TEST VERIFICATION - VER-2.
2 With the DRB read ECM Diagnostic Trouble Codes. This is to ensure power and
grounds to the ECM are operational.
NOTE: If the DRB will not read ECM DTC's, follow the NO RESPONSE TO
ECM (SCI only) symptom path, if vehicle will start. For NO START Condi-
tions follow the no start symptom in the Starting category.
Turn the ignition off.
Disconnect the ECM harness connectors.
Use Scope input cable CH7058, Cable to Probe adapter CH7062, and the red and
black test probes.
Connect the scope input cable to the channel one connector on the DRB. Attach the
red and black leads and the cable to probe adapter to the scope input cable.
With the DRBIIItselect Pep Module Tools.
Select lab scope.
Select Live Data.
Select 12 volt square wave.
Press F2 for Scope.
Press F2 and use the down arrow to set voltage range to 20 volts. Press F2 again
when complete.
Connect the Black lead to ground. Connect the Red lead to the PCI Bus circuit in the
ECM connector.
Turn the ignition on.
Observe the voltage display on the DRB Lab Scope.
Does the voltage pulse from 0 to approximately 7.5 volts?All
Ye s®Replace and program the Engine Control Module in accordance
with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
No®Repair the PCI Bus circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.
10
COMMUNICATION

Symptom:
*NO RESPONSE FROM ECM (SCI ONLY) - DIESEL ONLY
POSSIBLE CAUSES
CHECK ECM POWERS AND GROUNDS
CABIN HEATER ASSIST
SCI TRANSMIT CIRCUIT SHORTED TO VOLTAGE
SCI TRANSMIT CIRCUIT SHORTED TO GROUND
SCI TRANSMIT CIRCUIT OPEN
ENGINE CONTROL MODULE
TEST ACTION APPLICABILITY
1 Perform the symptom Checking ECM Power and Ground Circuits in the Driveability
category.
Did the vehicle pass this test?All
Ye s®Go To 2
No®Repair as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
2 Turn the ignition off.
Disconnect the ECM harness connectors.
Disconnect the DRB from the DLC.
Measure the resistance between ground and the SCI Transmit circuit.
Is the resistance below 5.0 ohms?All
Ye s®Go To 3
No®Go To 4
3 Turn the ignition off.
Disconnect the Cabin Heater Assist C1 harness connector.
Measure the resistance between ground and the SCI Transmit circuit.
Is the resistance below 5.0 ohms?All
Ye s®Repair the SCI Transmit circuit for a short to ground.
Perform ROAD TEST VERIFICATION - VER-2.
No®Replace the Cabin Heater Assist in accordance with the service
information.
Perform ROAD TEST VERIFICATION - VER-2.
4 Turn the ignition off.
Disconnect the DRB from the DLC.
Disconnect the ECM harness connectors.
Disconnect the Cabin Heater Assist C1 harness connector.
Turn the ignition on.
Measure the voltage of the SCI Transmit circuit at the DLC connector (cav 7).
Is the voltage above 1.0 volt?All
Ye s®Repair the SCI Transmit circuit for a short to voltage.
Perform ROAD TEST VERIFICATION - VER-2.
No®Go To 5
11
COMMUNICATION

TEST ACTION APPLICABILITY
5 Turn the ignition off.
Disconnect the ECM harness connectors.
Disconnect the DRB from the DLC.
Measure the resistance of the SCI Transmit circuit between the ECM connector and
the DLC.
Is the resistance below 5.0 ohms?All
Ye s®Go To 6
No®Repair the SCI Transmit circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.
6 If there are no possible causes remaining, view repair. All
Repair
Replace and program the Engine Control Module in accordance
with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
12
COMMUNICATION
*NO RESPONSE FROM ECM (SCI ONLY) - DIESEL ONLY ÐContinued

Symptom List:
P0100-MASS AIR FLOW SENSOR PLAUSIBILITY
P0100-MASS AIR FLOW SENSOR PLAUSIBILITY POSITIVE AREA
P0100-MASS AIR FLOW SENSOR SIGNAL VOLTAGE TOO HIGH
P0100-MASS AIR FLOW SENSOR SIGNAL VOLTAGE TOO LOW
P0100-MASS AIR FLOW SENSOR SUPPLY VOLTAGE TOO HIGH OR
LOW
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be P0100-MASS AIR FLOW SENSOR
PLAUSIBILITY.
When Monitored and Set Condition:
P0100-MASS AIR FLOW SENSOR PLAUSIBILITY
When Monitored: With the engine running.
Set Condition: The mass airflow measure does not correspond with the enigne load
measurements.
P0100-MASS AIR FLOW SENSOR SIGNAL VOLTAGE TOO HIGH
When Monitored: With the ignition on.
Set Condition: The Boost Pressure Sensor Signal voltage is above 4.5 volts.
P0100-MASS AIR FLOW SENSOR SIGNAL VOLTAGE TOO LOW
When Monitored: With the ignition on.
Set Condition: The Mass Air Flow Sensor Signal voltage is below 0.2 volt.
P0100-MASS AIR FLOW SENSOR SUPPLY VOLTAGE TOO HIGH OR LOW
When Monitored: With the ignition on.
Set Condition: The Sensor Reference Voltage9A9voltage to the MAF is below 4.8 volts or
above 5.2 volts for at least 100 ms.
POSSIBLE CAUSES
ECM - 5-VOLT SUPPLY CIRCUIT
ECM/PCM RELAY OUTPUT CIRCUIT OPEN
MAF SENSOR IDLE VOLTAGE
MAF SENSOR SIGNAL - FULL THROTTLE VOLTAGE
SENSOR GROUND OPEN
INTERMITTENT CONDITION
5-VOLT SUPPLY CIRCUIT OPEN
13
DRIVEABILITY - DIESEL

POSSIBLE CAUSES
MAF SENSOR SIGNAL CIRCUIT OPEN
5-VOLT SUPPLY CIRCUIT SHORTED TO THE SENSOR GROUND CIRCUIT
5-VOLT SUPPLY CIRCUIT SHORTED TO THE SENSOR GROUND CIRCUIT
MAF SENSOR SIGNAL CIRCUIT SHORTED TO GROUND
5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND
5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND
ECM SENSOR GROUND CIRCUIT OPEN
MAF SENSOR SIGNAL CIRCUIT SHORTED TO THE SENSOR GROUND CIRCUIT
5-VOLT SUPPLY CIRCUIT SHORTED TO VOLTAGE
5-VOLT SUPPLY CIRCUIT SHORTED TO VOLTAGE
MAF SENSOR CIRCUIT SHORTED TO VOLTAGE
ECM - MAF SENSOR SIGNAL CIRCUIT
TEST ACTION APPLICABILITY
1NOTE: If DTC P0641 or P0651 is present with this DTC, diagnose DTCs
P0641 and P0651 before diagnosing this DTC.
NOTE: Inspect the turbocharger inlet tube between the MAF Sensor and the
turbocharger for damage, restriction or poor connection. Any of these
conditions can cause a MAF Plausibility DTC.
Turn the ignition on.
With the DRBIIIt, erase the ECM DTCs.
Test drive the vehicle.
With the DRBIIIt, read the ECM DTCs.
Does the DRB III display a Mass Air Flow Sensor DTC?All
Ye s®Go To 2
No®Go To 20
2 Turn the ignition off.
Disconnect the MAF Sensor harness connector.
Turn the ignition on.
Measure the voltage of the 5-volt Supply circuit in MAF Sensor harness connector.
Is the voltage between 4.7 and 5.3 volts?All
Ye s®Go To 3
No®Go To 13
14
DRIVEABILITY - DIESEL
P0100-MASS AIR FLOW SENSOR PLAUSIBILITY ÐContinued

TEST ACTION APPLICABILITY
3 Turn the ignition off.
Disconnect the MAF Sensor harness connector.
Disconnect the ECM harness connectors.
Remove the ECM/PCM Relay from the PDC.
Connect a jumper wire between cavity 30 and cavity 87 of the ECM/PCM Relay
connector.
Turn the ignition on.
Measure the voltage of the MAF Sensor Signal circuit.
Is the voltage above 1.0 volt?All
Ye s®Repair the MAF Sensor Signal circuit for a short to voltage.
Perform ROAD TEST VERIFICATION - VER-2.
No®Go To 4
4 Turn the ignition off.
Disconnect the MAF Sensor harness connector.
Disconnect the ECM harness connectors.
Measure the resistance of the MAF Sensor Signal circuit.
Is the resistance below 10.0 ohms?All
Ye s®Go To 5
No®Repair the MAF Sensor Signal circuit for an open
Perform ROAD TEST VERIFICATION - VER-2.
5 Turn the ignition off.
Disconnect the MAF Sensor harness connector.
Disconnect the ECM harness connectors.
Measure the resistance between ground and the MAF Sensor Signal circuit.
Is the resistance below 1000 ohms?All
Ye s®Repair the MAF Sensor Signal circuit for a short to ground.
Perform ROAD TEST VERIFICATION - VER-2.
No®Go To 6
6 Turn the ignition off.
Disconnect the MAF Sensor harness connector.
Disconnect the ECM harness connectors.
Measure the resistance between the MAF Sensor Signal circuit and the Sensor
Ground circuit at of the MAF Sensor harness connector.
Is the resistance below 1000 ohms?All
Ye s®Repair the MAF Sensor Signal for a short to Sensor Ground .
Perform ROAD TEST VERIFICATION - VER-2.
No®Go To 7
7 Turn the ignition off.
Disconnect the MAF Sensor harness connector.
Connect a jumper wire between MAF Sensor Signal circuit and the 5-volt supply
circuit at the MAF Sensor harness connector .
With the DRBIII, read the MAF VOLTS.
Does the DRBIII display between 4.0 and 5.5 volts?All
Ye s®Go To 8
No®Replace and program the Engine Control Module in accordance
with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
15
DRIVEABILITY - DIESEL
P0100-MASS AIR FLOW SENSOR PLAUSIBILITY ÐContinued