sensor 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

check the shared circuits for possible problems
before continuing (i.e. Sensor Grounds or 5-Volt
Supply circuits). Refer to the appropriate wiring
diagrams to identify shared circuits.
MASS AIR FLOW SENSOR SIGNAL VOLTAGE
TOO HIGH
MASS AIR FLOW SENSOR SIGNAL VOLTAGE
TOO LOW
MASS AIR FLOW SENSOR SUPPLY VOLTAGE
TOO HIGH OR LOW
MASS AIR FLOW SENSOR PLAUSIBILITY
MASS AIR FLOW SENSOR SIGNAL PLAUSI-
BILITY POSITIVE AREA
BAROMETRIC PRESSURE CIRCUIT SIGNAL
VOLTAGE TOO HIGH
BAROMETRIC PRESSURE CIRCUIT SIGNAL
VOLTAGE TOO LOW
INTAKE AIR TEMP SENSOR SIGNAL VOLT-
AGE TOO HIGH
INTAKE AIR TEMP SENSOR SIGNAL VOLT-
AGE TOO LOW
ENGINE COOLANT TEMP SENSOR SIGNAL
VOLTAGE TOO HIGH
ENGINE COOLANT TEMP SENSOR SIGNAL
VOLTAGE TOO LOW
FUEL PRESS SENSOR CIRCUIT MALF SIG-
NAL VOLTAGE TOO HIGH
FUEL PRESS SENSOR CIRCUIT MALF SIG-
NAL VOLTAGE TOO LOW
FUEL PRESS SENSOR CIRCUIT MALF SUP-
PLY VOLTAGE TOO HIGH OR LOW
OIL TEMP SENSOR CIRCUIT MALF SIGNAL
VOLTAGE TOO HIGH
OIL TEMP SENSOR CIRCUIT MALF SIGNAL
VOLTAGE TOO LOW
CYLINDER 1-INJECTOR CIRCUIT OVERCUR-
RENT HIGH SIDE
CYLINDER 1-INJECTOR CIRCUIT OVERCUR-
RENT LOW SIDE
CYLINDER 1-INJECTOR CIRCUIT LOAD
DROP
CYLINDER 1-INJECTOR CIRCUIT CURRENT
DECREASE
CYLINDER 2-INJECTOR CIRCUIT OVERCUR-
RENT HIGH SIDE
CYLINDER 2-INJECTOR CIRCUIT OVERCUR-
RENT LOW SIDE
CYLINDER 2-INJECTOR CIRCUIT LOAD
DROP
CYLINDER 2-INJECTOR CIRCUIT CURRENT
DECREASE
CYLINDER 3-INJECTOR CIRCUIT OVERCUR-
RENT HIGH SIDE
CYLINDER 3-INJECTOR CIRCUIT OVERCUR-
RENT LOW SIDE
CYLINDER 3-INJECTOR CIRCUIT LOAD
DROPCYLINDER 3-INJECTOR CIRCUIT CURRENT
DECREASE
CYLINDER 4-INJECTOR CIRCUIT OVERCUR-
RENT HIGH SIDE
CYLINDER 4-INJECTOR CIRCUIT OVERCUR-
RENT LOW SIDE
CYLINDER 4-INJECTOR CIRCUIT LOAD
DROP
CYLINDER 4-INJECTOR CIRCUIT CURRENT
DECREASE
BOOST PRESSURE SENSOR SIGNAL VOLT-
AGE TOO HIGH
BOOST PRESSURE SENSOR SIGNAL VOLT-
AGE TOO LOW
BOOST PRESSURE SENSOR SUPPLY VOLT-
AGE TOO HIGH OR LOW
BOOST PRESSURE SENSOR PLAUSIBILITY
CKP POSITION SENSOR CIRCUIT OVER-
SPEED RECOGNITION
CKP POSITION SENSOR CIRCUIT DYNAMIC
PLAUSIBILITY
CKP POSITION SENSOR CIRCUIT STATIC
PLAUSIBILITY
CMP POSITION SENSOR CIRCUIT CMP/CKP
SYNC FAILURE
CMP POSITION SENSOR CIRCUIT DYNAMIC
PLAUSIBILITY
CMP POSITION SENSOR CIRCUIT STATIC
PLAUSIBILITY
CMP POSITION SENSOR CIRCUIT SIGNAL
FREQUENCY TOO HIGH
CMP POSITION SENSOR CIRCUIT FUEL
SHUT-OFF ACTIVATED
GLOW PLUG CIRCUIT A SHORT CIRCUIT
GLOW PLUG CIRCUIT A OPEN CIRCUIT
EGR SOLENOID CIRCUIT OPEN CIRCUIT
EGR SOLENOID CIRCUIT SHORT CIRCUIT
EGR SOLENOID CIRCUIT IMPROPER FLOW
FAN 1 CONTROL CIRCUIT OPEN CIRCUIT
FAN 1 CONTROL CIRCUIT SHORT CIRCUIT
FAN 2 CONTROL CIRCUIT OPEN CIRCUIT
FAN 2 CONTROL CIRCUIT SHORT CIRCUIT
VEHICLE SPEED SENSOR SIGNAL VOLTAGE
TOO HIGH
VEHICLE SPEED SENSOR FREQUENCY TOO
HIGH
VEHICLE SPEED SENSOR HIGH LEVEL DU-
RATION
VEHICLE SPEED SENSOR PLAUSIBILITY
BATTERY TEMP SENSOR SIGNAL VOLTAGE
TOO HIGH
BATTERY TEMP SENSOR SIGNAL VOLTAGE
TOO LOW
OIL PRESS SENSOR CKT MALF PLAUSIBIL-
ITY
4
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

J1850 COMMUNICATION BUS SPI ERROR
J1850 COMMUNICATION BUS RECEIVE TIME-
OUT
J1850 COMMUNICATION BUS UNAUTHO-
RIZED RESET
EEPROM PLAUSIBILITY CHECKSUM ERROR
EEPROM PLAUSIBILITY VIN CHECKSUM
ERROR
EEPROM PLAUSIBILITY COMMUNICATION
ERROR
EEPROM PLAUSIBILITY WRITE ERROR
EEPROM PLAUSIBILITY VARIATION NUM-
BER ERROR
EEPROM PLAUSIBILITY CODE WORD IN-
CORRECT OR MISSING
SKIM SYSTEM SKIM ERROR
SKIM SYSTEM WRITE ACCESS TO EEPROM
FAILURE
SKIM SYSTEM INVALID SECRET KEY IN EE-
PROM
SKIM SYSTEM KEY COMMUNICATION
TIMED OUT
SKIM SYSTEM INVALID KEY CODE RE-
CEIVED
EEPROM RECOVERY OCCURRED
EEPROM REDUNDANT OVERRUN MONI-
TORING
EEPROM QUANTITY STOP
EEPROM COMMUNICATION ERROR
EEPROM COMMUNICATION NOT VERIFIED
ACC PEDAL POSITION SENSOR 1 CKT SIG-
NAL VOLTAGE TOO HIGH
ACC PEDAL POSITION SENSOR 1 CKT SIG-
NAL VOLTAGE TOO LOW
ACC PEDAL POSITION SENSOR 1 CKT SUP-
PLY VOLTAGE TOO HIGH OR LOW
ACC PEDAL POSITION SENSOR 1 CKT PLAU-
SIBILITY WITH POTENTIOMETER
ACC PEDAL POSITION SENSOR 1 CKT PLAU-
SIBILITY WITH BRAKE SWITCH
ACC PEDAL POSITION SENSOR 1 CKT PLAU-
SIBILITY
3.3.4 SKIM DIAGNOSTIC TROUBLE CODES
ANTENNA FAILURE
COP FAILURE
EEPROM FAILURE
PCM STATUS FAILURE
INTERNAL FAULT
RAM FAILURE
ROLLING CODE FAILURE
SERIAL LINK EXTERNAL FAULT
SERIAL LINK INTERNAL FAULT
STACK OVERFLOW FAILURE
TRANSPONDER COMMUNICATION FAILURE
TRANSPONDER CRC (CYCLIC REDUN-
DANCY CHECK) FAILURE
TRANSPONDER ID MISMATCHTRANSPONDER RESPONSE MISMATCH
VIN MISMATCH
3.3.5 HANDLING NO TROUBLE CODE
PROBLEMS
After reading Section 3.0 (System Description
and Functional Operation), you should have a bet-
ter understanding of the theory and operation of the
on-board diagnostics, and how this relates to the
diagnosis of a vehicle that may have a driveability-
related symptom or complaint.
3.4 USING THE DRBIIIT
Refer to the DRBIIItuser 's guide for instructions
and assistance with reading the DTCs, erasing the
DTCs, lab scope usage and other DRBIIItfunc-
tions.
3.4.1 DRBIIITDOES NOT POWER UP
If the LEDs do not light or no sound is emitted at
start up, check for loose cable connections or a bad
cable. Check the vehicle battery voltage at data link
connector cavity 16. A minimum of 11.0 volts is
required to adequately power the DRB. Check for
proper ground connection at data link connector
cavities 4 and 5.
If all connections are proper between the
DRBIIItand the vehicle or other devices, and the
vehicle battery is fully charged, an inoperative
DRBIIItmay be the result of a faulty cable or
vehicle wiring. For a blank screen, refer to the
appropriate diagnostic manual.
3.4.2 DISPLAY IS NOT VISIBLE
Low temperatures will affect the visibility of the
display. Adjust the contrast to compensate for this
condition.
6
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 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

TEST ACTION APPLICABILITY
8 Turn the ignition off.
Disconnect the MAF Sensor harness connector.
Disconnect the ECM harness connectors.
Measure the resistance of the Sensor Ground circuit between the MAF Sensor and
the ECM.
Is the resistance below 10.0 ohms?All
Ye s®Go To 9
No®Repair the Sensor Ground circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.
9 Turn the ignition off.
Disconnect the MAF Sensor harness connector.
Measure the voltage between the 5-volt Supply circuit and the Sensor Ground circuit
at the MAF Sensor harness connector.
Is the voltage above 4.5 volts?All
Ye s®Go To 10
No®Replace and program the ECM in accordance with the Service
Information.
Perform ROAD TEST VERIFICATION - VER-2.
10 Turn the ignition off.
Disconnect the MAF Sensor harness connector.
With the DRBIIIt, actuate the ECM/PCM Relay.
Measure the voltage of the 12-volt Supply circuit at the MAF Sensor harness
connector
Is the voltage above 10.0 volts?All
Ye s®Go To 11
No®Repair the ECM/PCM Relay Output circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.
11 Turn the ignition off.
NOTE: Inspect the turbocharger inlet tube between the MAF Sensor and the
Turbocharger. Ensure the airflow tube properly is secured at each end and
that there is no damage, restrictions or air leaks in the tube.
With a voltmeter, backprobe the MAF Sensor Signal circuit at the MAF Sensor
harness connector.
Allow the engine to idle for at least 2 minutes.
NOTE: The engine speed must be approximately 900 rpm for this test to be
valid.
Is the voltage between 2.1 and 2.7 volts?All
Ye s®Go To 12
No®Replace the Mass Air Flow Sensor in accordance with the Service
Information.
Perform ROAD TEST VERIFICATION - VER-2.
16
DRIVEABILITY - DIESEL
P0100-MASS AIR FLOW SENSOR PLAUSIBILITY ÐContinued