
Symptom:
P0110-INTAKE AIR TEMP SENSOR CIRCUIT SIGNAL VOLTAGE
TOO LOW
When Monitored and Set Condition:
P0110-INTAKE AIR TEMP SENSOR CIRCUIT SIGNAL VOLTAGE TOO LOW
When Monitored: With the ignition on.
Set Condition: The Intake Air Temperature Sensor Signal voltage is below 0.21 volt.
POSSIBLE CAUSES
INTERMITTENT CONDITION
INTAKE AIR TEMP SENSOR SIGNAL CIRCUIT SHORTED TO GROUND
TURBOCHARGER BOOST PRESSURE/IAT SENSOR
ENGINE CONTROL MODULE
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRB, erase ECM DTCs.
Monitor the DRB for ECM DTCs.
Did this DTC reset?All
Ye s®Go To 2
No®Go To 5
2 Turn the ignition off.
Disconnect the ECM harness connectors.
Disconnect the Boost Pressure/IAT Sensor harness connector.
Measure the resistance between ground and the Intake Air Temperature Sensor
Signal circuit.
Is the resistance above 1000 ohms?All
Ye s®Go To 3
No®Repair the Intake Air Temperature Sensor Signal circuit for a
short to ground.
Perform ROAD TEST VERIFICATION - VER-2.
3 Turn the ignition off.
Disconnect the Boost Pressure/IAT Sensor harness connector.
Turn the ignition on.
Monitor the DRB for ECM DTCs.
Does the DRB display P0110 INTAKE AIR TEMP SIGNAL VOLTAGE TOO HIGH?All
Ye s®Replace the Turbocharger Boost Pressure/Intake Air Tempera-
ture Sensor.
Perform ROAD TEST VERIFICATION - VER-2.
No®Go To 4
27
DRIVEABILITY - DIESEL

Symptom:
P0190-FUEL PRESS SENSOR CIRCUIT MALF SIGNAL VOLTAGE
TOO HIGH
When Monitored and Set Condition:
P0190-FUEL PRESS SENSOR CIRCUIT MALF SIGNAL VOLTAGE TOO HIGH
When Monitored: With the ignition on.
Set Condition: The Fuel Rail Pressure Sensor Signal voltage is above 4.8 volts.
POSSIBLE CAUSES
ECM - FUEL PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO VOLTAGE
ECM - FUEL PRESSURE SENSOR SIGNAL OPEN
FUEL PRESSURE SENSOR SIGNAL CIRCUIT OPEN
FUEL PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO VOLTAGE
SENSOR GROUND CIRCUIT OPEN
INTERMITTENT CONDITION
5-VOLT SUPPLY CIRCUIT OPEN
SENSOR GROUND CIRCUIT SHORTED TO VOLTAGE
FUEL PRESSURE SENSOR
ENGINE CONTROL MODULE
TEST ACTION APPLICABILITY
1WARNING: THE FUEL INJECTION PUMP SUPPLIES HIGH PRESSURE
FUEL TO EACH INDIVIDUAL INJECTOR THROUGH HIGH-PRESSURE
FUEL LINES. FUEL UNDER HIGH PRESSURE CAN PENETRATE SKIN
AND CAUSE PERSONAL INJURY. WEAR SAFETY GOGGLES AND ADE-
QUATE PROTECTIVE CLOTHING.
Turn the ignition on.
With the DRB III, erase ECM DTCs.
Cycle the ignition key on and off several times, leaving the key on for at least 10
seconds at a time.
With the DRB III, read ECM DTCs.
Did this DTC reset?All
Ye s®Go To 2
No®Go To 10
34
DRIVEABILITY - DIESEL

Symptom:
P0190-FUEL PRESS SENSOR CIRCUIT MALF SIGNAL VOLTAGE
TOO LOW
When Monitored and Set Condition:
P0190-FUEL PRESS SENSOR CIRCUIT MALF SIGNAL VOLTAGE TOO LOW
When Monitored: With the ignition on.
Set Condition: The Fuel Rail Pressure Sensor Signal voltage is below 0.2 volt.
POSSIBLE CAUSES
FUEL PRESSURE SENSOR
INTERMITTENT CONDITION
FUEL PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO GROUND
FUEL PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO SENSOR GROUND
ECM - FUEL PRESSURE SENSOR SIGNAL SHORTED TO GROUND
TEST ACTION APPLICABILITY
1WARNING: THE FUEL INJECTION PUMP SUPPLIES HIGH PRESSURE
FUEL TO EACH INDIVIDUAL INJECTOR THROUGH HIGH-PRESSURE
FUEL LINES. FUEL UNDER HIGH PRESSURE CAN PENETRATE SKIN
AND CAUSE PERSONAL INJURY. WEAR SAFETY GOGGLES AND ADE-
QUATE PROTECTIVE CLOTHING.
NOTE: If DTC P0641 or P0651 is present with this DTC, diagnose DTCs
P0641 and P0651 before diagnosing this DTC.
Turn the ignition on.
With the DRB III, erase ECM DTCs.
Cycle the ignition key on and off several times, leaving the key on for at least 10
seconds at a time.
With the DRB III, read ECM DTCs.
Did this DTC reset?All
Ye s®Go To 2
No®Go To 6
2 Turn the ignition off.
Disconnect the Fuel Pressure Sensor harness connector.
Measure the voltage of the Fuel Pressure Sensor Signal circuit.
Is the voltage between 4.7 and 5.3 volts?All
Ye s®Replace the Fuel Pressure Sensor.
Perform ROAD TEST VERIFICATION - VER-2.
No®Go To 3
38
DRIVEABILITY - DIESEL

Symptom:
P0235-BOOST PRESSURE SENSOR PLAUSIBILITY
When Monitored and Set Condition:
P0235-BOOST PRESSURE SENSOR PLAUSIBILITY
When Monitored: With the engine speed below 950 rpm.
Set Condition: When the engine is idling, the turbocharger boost pressure sensor input
does not agree with the atmospheric pressure sensor input for at least 5 seconds.
POSSIBLE CAUSES
INTERMITTENT CONDITION
HIGH RESISTANCE IN THE BOOST PRESSURE SENSOR SIGNAL CIRCUIT
HIGH RESISTANCE IN THE BOOST PRESSURE SENSOR GROUND CIRCUIT
HIGH RESISTANCE IN THE 5-VOLT SUPPLY CIRCUIT
TURBOCHARGER BOOST PRESSURE/INTAKE AIR TEMPERATURE SENSOR
ENGINE CONTROL MODULE
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRB, erase ECM DTCs.
Turn the ignition off, wait 30 seconds, then start and idle the engine for at least 30
seconds.
NOTE: Engine idle speed must be below 870 RPM.
With the DRB, read ECM DTCs.
Did this DTC reset?All
Ye s®Go To 2
No®Go To 6
2 Turn the ignition off.
Disconnect the Turbocharger Boost Pressure/IAT Sensor harness connector.
Disconnect the ECM harness connectors.
Measure the resistance of the Boost Pressure Sensor Signal circuit.
Is the resistance below 5.0 ohms?All
Ye s®Go To 3
No®Repair the Boost Pressure Sensor Signal circuit for high resis-
tance.
Perform ROAD TEST VERIFICATION - VER-2.
62
DRIVEABILITY - DIESEL

TEST ACTION APPLICABILITY
3 Turn the ignition off.
Disconnect the Turbocharger Boost Pressure/IAT Sensor harness connector.
Disconnect the ECM harness connectors.
Measure the resistance of the Sensor Ground circuit.
Is the resistance below 5.0 ohms?All
Ye s®Go To 4
No®Repair the Boost Pressure Sensor Ground circuit for high resis-
tance.
Perform ROAD TEST VERIFICATION - VER-2.
4 Turn the ignition off.
Disconnect the Turbocharger Boost Pressure/IAT Sensor harness connector.
Disconnect the ECM harness connectors.
Measure the resistance of the 5-volt Supply circuit.
Is the resistance below 5.0 ohms?All
Ye s®Go To 5
No®Repair the 5-volt Supply circuit for high resistance.
Perform ROAD TEST VERIFICATION - VER-2.
5 Turn the ignition off.
Replace the Turbocharger Boost Pressure/Intake Air Temperature Sensor.
Turn the ignition on.
With the DRB, erase ECM DTCs.
Test drive the vehicle, pausing several times to cycle the ignition.
Monitor the DRB for ECM DTCs.
Did this DTC reset?All
Ye s®Replace and program the Engine Control Module in accordance
with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
No®The repair is complete.
Perform ROAD TEST VERIFICATION - VER-2.
6WARNING: WHEN THE ENGINE IS OPERATING, DO NOT STAND IN A
DIRECT LINE WITH THE FAN. DO NOT PUT YOUR HANDS NEAR THE
PULLEYS, BELTS OR FAN. DO NOT WEAR LOOSE CLOTHING.
NOTE: The conditions that set the DTC are not present at this time. The
following list may help in identifying the intermittent condition.
With the engine running at normal operating temperature, monitor the DRB
parameters related to the DTC while wiggling the wiring harness. Look for param-
eter values to change and/or a DTC to set.
Review the DTC When Monitored and Set Conditions. If possible, try to duplicate the
conditions under which the DTC was set.
Refer to any Technical Service Bulletins (TSB) that may apply.
Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or
partially broken wires.
Visually inspect the related wiring harness connectors. Look for broken, bent, pushed
out, or corroded terminals.
Were any of the above conditions present?All
Ye s®Repair as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
No®Test Complete.
63
DRIVEABILITY - DIESEL
P0235-BOOST PRESSURE SENSOR PLAUSIBILITY ÐContinued

TEST ACTION APPLICABILITY
7 Turn the ignition off.
NOTE: Ensure all harness connectors are connected.
Turn the ignition on.
Measure the voltage of the Boost Pressure Sensor Signal circuit by backprobing ECM
harness connector C1, cavity 40.
Is the voltage above 4.5 volts?All
Ye s®Replace the Turbocharger Boost Pressure/Intake Air Tempera-
ture Sensor.
Perform ROAD TEST VERIFICATION - VER-2.
No®Go To 8
8 Turn the ignition on.
With the DRB, read ECM DTCs.
Did this DTC reset?All
Ye s®Replace and program the Engine Control Module in accordance
with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
No®Ensure good terminal contact between the Turbocharger Boost
Pressure/IAT Sensor harness connector and the sensor. The
repair is complete.
Perform ROAD TEST VERIFICATION - VER-2.
9WARNING: WHEN THE ENGINE IS OPERATING, DO NOT STAND IN A
DIRECT LINE WITH THE FAN. DO NOT PUT YOUR HANDS NEAR THE
PULLEYS, BELTS OR FAN. DO NOT WEAR LOOSE CLOTHING.
NOTE: The conditions that set the DTC are not present at this time. The
following list may help in identifying the intermittent condition.
With the engine running at normal operating temperature, monitor the DRB
parameters related to the DTC while wiggling the wiring harness. Look for param-
eter values to change and/or a DTC to set.
Review the DTC When Monitored and Set Conditions. If possible, try to duplicate the
conditions under which the DTC was set.
Refer to any Technical Service Bulletins (TSB) that may apply.
Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or
partially broken wires.
Visually inspect the related wiring harness connectors. Look for broken, bent, pushed
out, or corroded terminals.
Were any of the above conditions present?All
Ye s®Repair as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
No®Test Complete.
66
DRIVEABILITY - DIESEL
P0235-BOOST PRESSURE SENSOR SIGNAL VOLTAGE TOO HIGH Ð
Continued

Symptom:
P0235-BOOST PRESSURE SENSOR SUPPLY VOLTAGE TOO HIGH
OR LOW
When Monitored and Set Condition:
P0235-BOOST PRESSURE SENSOR SUPPLY VOLTAGE TOO HIGH OR LOW
When Monitored: With the ignition on.
Set Condition: The Sensor Reference Voltage9B9voltage to the Boost Pressure Sensor is
below 4.8 volts or above 5.2 volts for at least 100 ms.
POSSIBLE CAUSES
INTERMITTENT CONDITION
5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND
5-VOLT SUPPLY CIRCUIT SHORTED TO SENSOR GROUND
5-VOLT SUPPLY CIRCUIT SHORTED TO VOLTAGE
APP SENSOR 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND
APP SENSOR 5-VOLT SUPPLY CIRCUIT SHORTED TO VOLTAGE
ENGINE CONTROL MODULE
TEST ACTION APPLICABILITY
1NOTE: If DTC P0641 or P0651 is present with this DTC, diagnose DTCs
P0641 and P0651 before diagnosing this DTC.
Turn the ignition on.
With the DRB, erase ECM DTCs.
Turn the ignition off, wait 30 seconds, then turn the ignition on.
With the DRB, read ECM DTCs.
Did this DTC reset?All
Ye s®Go To 2
No®Go To 7
2 Turn the ignition off.
Disconnect the Boost Pressure/IAT 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 between ground and the 5-volt Supply circuit at the Boost
Pressure/IAT Sensor harness connector.
Is the voltage above 1.0 volt?All
Ye s®Repair the 5-volt Supply circuit for a short to voltage.
Perform ROAD TEST VERIFICATION - VER-2.
No®Go To 3
70
DRIVEABILITY - DIESEL

Symptom:
P0335-CKP POSITION SENSOR CIRCUIT OVERSPEED RECOGNI-
TION
When Monitored and Set Condition:
P0335-CKP POSITION SENSOR CIRCUIT OVERSPEED RECOGNITION
When Monitored: With the engine running.
Set Condition: The engine speed sensor signal indicates engine speed is above 5100 RPM
for at least 500 milliseconds. NOTE: Engine damage is possible when the engine speed
exceeds 5100 RPM.
POSSIBLE CAUSES
CHECK FOR OTHER DTCS
ENGINE CONTROL MODULE
OPEN SHIELD CIRCUIT
REPLACE THE CRANKSHAFT POSITION SENSOR
INTERMITTENT CONDITION
TEST ACTION APPLICABILITY
1CAUTION: Engine damage is possible when engine speed exceeds 5000
RPM.
NOTE: This DTC indicates the Engine Speed Sensor has seen an engine
speed above 5000 RPM. This can occur if the vehicle is in 5th gear and the
vehicle operator performs a downshift and accidentally downshifts from
5th gear to 2nd gear.
Turn the ignition on.
With the DRB, check for other Engine Speed Sensor DTCs.
Are other Engine Speed Sensor DTCs present?All
Ye s®Refer to symptom list for problems related to other DTCs before
continuing.
Perform ROAD TEST VERIFICATION - VER-2.
No®Go To 2
2 Turn the ignition on.
With the DRB, erase ECM DTCs.
Test drive the vehicle and monitor the DRB for ECM DTCs.
Did this DTC reset?All
Ye s®Go To 3
No®Go To 5
73
DRIVEABILITY - DIESEL