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
TEST ACTION APPLICABILITY
7WARNING: 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.
72
DRIVEABILITY - DIESEL
P0235-BOOST PRESSURE SENSOR SUPPLY VOLTAGE TOO HIGH OR
LOW Ð
Continued
TEST ACTION APPLICABILITY
3 Turn the ignition off.
Disconnect the ECM harness connectors.
Disconnect the CKP Sensor harness connector.
Measure the resistance of the Shield circuit.
Is the resistance below 10.0 ohms?All
Ye s®Go To 4
No®Repair the Shield circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.
4 Replace the Crankshaft Position Sensor in accordance with the Service Information.
With the DRB, erase ECM DTCs.
Perform several drive cycles, turning the ignition off for at least 10 seconds between
each drive cycle.
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. Refer to the Service Information to check
for engine mechanical problems that may have occurred due to
excessive engine speed.
Perform ROAD TEST VERIFICATION - VER-2.
5WARNING: 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.
Check the Engine Speed Sensor wiring harness for incorrect routing which may
cause EMI interference.
Were any of the above conditions present?All
Ye s®Repair as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
No®Test Complete.
74
DRIVEABILITY - DIESEL
P0335-CKP POSITION SENSOR CIRCUIT OVERSPEED RECOGNITION
Ð
Continued
Symptom:
P0340-CKP POSITION SENSOR CIRCUIT DYNAMIC PLAUSIBIL-
ITY
When Monitored and Set Condition:
P0340-CKP POSITION SENSOR CIRCUIT DYNAMIC PLAUSIBILITY
When Monitored: The engine speed is above 790 RPM.
Set Condition: The ECM detects a change in engine speed that has occurred more rapidly
than the engine is capable of changing speed.
POSSIBLE CAUSES
ENGINE CONTROL MODULE
INTERMITTENT CONDITION
CRANKSHAFT POSITION SENSOR SIGNAL CIRCUIT(S) SHORTED TO GROUND
CKP SENSOR CIRCUITS SHORTED TOGETHER
CKP SENSOR SIGNAL CIRCUITS OPEN
CKP SENSOR SIGNAL CIRCUIT(S) SHORTED TO VOLTAGE
CRANKSHAFT POSITION SENSOR
TEST ACTION APPLICABILITY
1 Attempt to start the engine.
Did the engine start?All
Ye s®Go To 2
No®Go To 3
2WARNING: 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.
75
DRIVEABILITY - DIESEL
Symptom:
P0340-CMP POSITION SENSOR CIRCUIT CMP/CKP SYNC FAIL-
URE
When Monitored and Set Condition:
P0340-CMP POSITION SENSOR CIRCUIT CMP/CKP SYNC FAILURE
When Monitored: With the engine running.
Set Condition: The ECM determines that the camshaft position sensor signal frequency
is not plausible with the crankshaft position sensor signal frequency.
POSSIBLE CAUSES
CHECK CAMSHAFT POSITION SENSOR SIGNAL
CHECK CRANKSHAFT POSITION SENSOR SIGNAL
CHECKING CKP SENSOR FOR DAMAGE
CHECKING CMP SENSOR FOR DAMAGE
ENGINE CONTROL MODULE
GEAR ALIGNMENT
INTERMITTENT CONDITION
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRBIIIt, erase the ECM DTCs.
Attempt to start the engine.
With the DRBIIIt, read the ECM DTCs.
Does the DRB III display this DTC?All
Ye s®Go To 3
No®Go To 2
2 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 this DTC?All
Ye s®Go To 3
No®Go To 8
3 Turn the ignition off.
Remove the CMP Sensor.
Inspect the camshaft Position Sensor for conditions such as loose mounting screws,
damage or debris, also check the camshaft for cracked teeth.
Is there any evidence of these conditions?All
Ye s®Repair as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
No®Go To 4
77
DRIVEABILITY - DIESEL
TEST ACTION APPLICABILITY
4 Turn the ignition off.
Remove the CKP Sensor.
Inspect the Crankshaft Position Sensor for conditions such as loose mounting screws,
damage or debris.
Is there any evidence of these conditions?All
Ye s®Repair as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
No®Go To 5
5 Turn the ignition off.
Using the DRB lab scope, backprobe the CMP Sensor Signal circuit at the CMP
Sensor harness connector.
Start the engine, if the engine will not start, crank the engine for several seconds
while monitoring the DRB.
NOTE: Refer to Charts and Graphs to view a correct CMP Sensor signal.
Does the DRB display a steady clean CMP Signal pattern?All
Ye s®Go To 6
No®Perform Test for DTC P0340-Camshaft Position Sensor Circuit
Static Plausibility.
Perform ROAD TEST VERIFICATION - VER-2.
6 Turn the ignition off.
Using the DRB lab scope, backprobe both of the CKP Sensor Signal circuits at the
CKP Sensor harness connector.
NOTE: Refer to Charts and Graphs to view a correct CKP Sensor signal.
Start the engine, if the engine will not start, crank the engine for several seconds
while monitoring the DRB.
Does the DRB display a steady clean CKP Signal pattern for each circuit?All
Ye s®Go To 7
No®Perform Test for DTC P0340-Crankshaft Position Sensor Circuit
Dynamic Plausibility.
Perform ROAD TEST VERIFICATION - VER-2.
7 Refer to the Service Information and check alignment of the camshaft sprocket,
crankshaft sprocket and injection pump sprocket.
Are all of the sprockets aligned correctly?All
Ye s®Replace and program the Engine Control Module in accordance
with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
No®Repair or adjust as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
78
DRIVEABILITY - DIESEL
P0340-CMP POSITION SENSOR CIRCUIT CMP/CKP SYNC FAILURE Ð
Continued
TEST ACTION APPLICABILITY
8WARNING: 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.
79
DRIVEABILITY - DIESEL
P0340-CMP POSITION SENSOR CIRCUIT CMP/CKP SYNC FAILURE Ð
Continued
TEST ACTION APPLICABILITY
7 Turn the ignition on.
With the DRB III, read the CMP Sensor RPM.
Connect one end of a jumper wire to the CMP signal circuit and tap the other end of
the jumper wire to Sensor Ground at the CMP harness connector while observing the
DRB.
Does the DRB III display an RPM change while tapping the jumper wire to Sensor
Ground?All
Ye s®Go To 8
No®Replace and program the ECM in accordance with the Service
Information.
Perform ROAD TEST VERIFICATION - VER-2.
8 Turn the ignition off.
With the DRB III lab scope lead, backprobe the CMP Signal circuit.
Set the DRB lab scope settings as follows: Time = 0.1s/Div, 20 volts scale, Offset =
0.00volts, Probe = X10, Coupling = DC
While observing the DRB III display, crank the engine.
NOTE: The DRB III should display a digital signal (square wave) similar to
that shown in the support material.
Does the DRB display an uninterrupted digital signal (square wave)?All
Ye s®Go To 9
No®Replace the Camshaft Position Sensor in accordance with the
Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
9 Turn the ignition on.
Remove the CMP Sensor.
Inspect the camshaft for conditions such as loose mounting screws, damage, debris or
cracked teeth.
Is there any evidence of these conditions?All
Ye s®Repair as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
No®Replace the Camshaft Position Sensor.
Perform ROAD TEST VERIFICATION - VER-2.
10 Turn the ignition off.
Disconnect the CMP Sensor harness connector.
Disconnect the ECM harness connectors.
Measure the resistance of the CMP Sensor Signal circuit.
Is the resistance below 10.0 ohms?All
Ye s®Go To 11
No®Repair the CMP Sensor Signal circuit for an open
Perform ROAD TEST VERIFICATION - VER-2.
11 Turn the ignition off.
Disconnect the CMP Sensor harness connector.
Disconnect the ECM harness connectors.
Measure the resistance between ground and the CMP Sensor Signal circuit.
Is the resistance below 1000 ohms?All
Ye s®Repair the CMP Sensor Signal circuit for a short to ground.
Perform ROAD TEST VERIFICATION - VER-2.
No®Go To 12
82
DRIVEABILITY - DIESEL
P0340-CMP POSITION SENSOR CIRCUIT SIGNAL FREQUENCY TOO
HIGH Ð
Continued