Page 1287 of 5267

P0460-FUEL LEVEL SENDING UNIT NO CHANGE OVER MILES
For a complete wiring diagramRefer to Section 8W.
When Monitored:
Engine running and fuel level either below 15% or above 85% of capacity.
Set Condition:
The PCM sees low fuel, less than 15%, for more than 120 miles or fuel level does not change by at least 4%
for more than 250 miles.
Possible Causes
PHYSICALLY DAMAGED/DEFORMED/OBSTRUCTED FUEL TANK
FUEL LEVEL SENSOR
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
1.CHECKING FOR A DAMAGED/DEFORMED/OBSTRUCTED FUEL TANK
Turn the ignition off.
WARNING: WARNING: The fuel system is under a constant pressure, even with the engine off. Before test-
ing or servicing any fuel system hose, fitting or line, the fuel system pressure must be released.
Inspect the outside of the fuel tank for defects.
Remove the fuel tank.
Remove the fuel pump module from the fuel tank.
Inspect the inside of the fuel tank for any obstructions or deformities.
Is the fuel tank free from defects?
Ye s>>
Go To 2
No>>
Repair or replace the fuel tank as necessary.
Perform POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
2.FUEL LEVEL SENSOR
If there are no possible causes remaining, view repair.
Repair
Replace the Fuel Level Sensor.
Perform POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
Page 1290 of 5267

3.(N4) FUEL LEVEL SIGNAL CIRCUIT SHORTED TO GROUND
Turn the ignition off.
Disconnect the C3 PCM harness connector.
Measure the resistance between ground and the (N4) Fuel Level Signal
circuit in the Fuel Pump Module harness connector.
Istheresistancebelow100ohms?
Ye s>>
Repair the short to ground in the (N4) Fuel Level Signal cir-
cuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 4
4.(N4) FUEL LEVEL SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT
Measure the resistance between the (N4) Fuel Level Signal circuit and
the (K900) Sensor Ground circuit in the Fuel Pump Module harness
connector.
Is the resistance below 5.0 ohms?
Ye s>>
Repair the short between the (K900) Sensor Ground circuit
and the (N4) Fuel Level Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 5
5.PCM
NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal
push out. Repair as necessary.
Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and
Ground circuits.
Were there any problems found?
Ye s>>
Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Replace and program the Powertrain Control Module per Service Information.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
Page 1294 of 5267
5.(K900) SENSOR GROUND CIRCUIT OPEN
Measure the resistance of the (K900) Sensor Ground circuit from the
Fuel Pump Module harness connector to the PCM harness connector.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 6
No>>
Repair the open in the (K900) Sensor Ground circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
6.PCM
NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal
push out. Repair as necessary.
Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and
Ground circuits.
Were there any problems found?
Ye s>>
Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Replace and program the Powertrain Control Module per Service Information.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
Page 1296 of 5267

When Monitored:
Engine Temperature greater than 104 Deg F, MAP vacuum approximately 15
to 16inches of mercury and
Engine RPM between 1400 and 3000 rpm.
Set Condition:
No Vehicle Speed Signal for more than 15 seconds on two consecutive trips.
Possible Causes
(B22) VEHICLE SPEED SIGNAL CIRCUIT SHORTED TO VOLTAGE
(B22) VEHICLE SPEED SIGNAL CIRCUIT OPEN BETWEEN CAB AND PCM
(B22) VEHICLE SPEED SIGNAL CIRCUIT SHORTED TO GROUND
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
1.GOOD TRIP EQUAL TO ZERO
Ignition on, engine not running.
NOTE: With the scan tool check for any related DTCs that may be present in theABS/RWAL Module or TCM,
diagnose any ABS/RWAL Module DTC’s before continuing.
With the scan tool, read DTCs and record the related Freeze Frame data.
Is the Good Trip Counter displayed and equal to zero?
Ye s>>
Go To 2
No>>
Refer to the INTERMITTENT CONDTION Diagnostic Procedure.
Perform POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
2.(B22) VEHICLE SPEED SENSOR SIGNAL CIRCUIT SHORT TO VOLTAGE
Turn the ignition off.
Disconnect the PCM harness connectors.
Disconnect the CAB Module harness connector.
Ignition on, engine not running.
Measure the voltage of the (B22) Vehicle Speed Signal circuit in the
CAB Module or PCM harness connector.
Is the voltage above 4.9 volts?
Ye s>>
Repair the short to voltage in the (B22) Vehicle Speed Sig-
nal circuit between the CAB and PCM.
Perform POWERTRAIN VERIFICATION TEST. (Refer to 9 -
ENGINE - STANDARD PROCEDURE)
No>>
Go To 3
Page 1297 of 5267

3.(B22) VEHICLE SPEED SENSOR SIGNAL CIRCUIT OPEN BETWEEN CAB AND PCM
Turn the ignition off.
Measure the resistance of the (B22) Vehicle Speed Signal circuit
between the PCM harness connector and the CAB Module harness
connector.
Is the resistance above 5.0 ohms?
Ye s>>
Repair the open in the (B22) Vehicle Speed Signal circuit
between the CAB and PCM.
Perform POWERTRAIN VERIFICATION TEST. (Refer to 9 -
ENGINE - STANDARD PROCEDURE)
No>>
Go To 4
4.(B22) VEHICLE SPEED SENSOR SIGNAL CIRCUIT SHORT TO GROUND
Measure the resistance between ground and the (B22) Vehicle Speed
Signal circuit at the PCM harness connector.
Istheresistancebelow100ohms?
Ye s>>
Repair the short to ground in the (B22) Vehicle Speed Sig-
nal circuit between the CAB and PCM.
Perform POWERTRAIN VERIFICATION TEST. (Refer to 9 -
ENGINE - STANDARD PROCEDURE)
No>>
Go To 5
5.PCM
NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal
push out. Repair as necessary.
Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and
Ground circuits.
If there are no possible causes remaining, view repair.
Repair
Replace and program the Powertrain Control Module per Service Information.
Perform POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
Page 1299 of 5267

When Monitored:
At power-up and battery voltage greater than 11.5 volts.
Set Condition:
The PCM senses a short to ground or battery voltage on any of the four Idle AirControl (IAC) driver circuits
for 100 ms while the IAC motor is active.
Possible Causes
(K40) IAC #1 DRIVER CIRCUIT SHORTED TO (K60) #2, (K39) #3, OR (K59) #4 IAC DRIVER CIRCUITS
(K60) IAC #2 DRIVER CIRCUIT SHORTED TO (K39) IAC #3 OR (K59) IAC #4
(K39) IAC #3 DRIVER CIRCUIT SHORTED TO (K59) IAC #4 DRIVER CIRCUIT
IAC DRIVER CIRCUIT SHORTED TO VOLTAGE
IAC DRIVER CIRCUIT SHORTED TO GROUND
IAC MOTOR
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
1.GOOD TRIP EQUAL TO ZERO
Ignition on, engine not running.
With the scan tool, read DTCs and record the related Freeze Frame data.
Is the Good Trip Counter displayed and equal to zero?
Ye s>>
Go To 2
No>>
Refer to the INTERMITTENT CONDITIONSymptom (Diagnostic Procedure).
Perform POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
2.IAC #1 DRIVER CIRCUIT SHORTED TO #2, #3, OR #4
Turn the ignition off.
Disconnect the IAC Motor harness connector.
Disconnect the C1 PCM harness connector.
NOTE: The following steps are checking for a short between the
IAC Driver circuits.
Measure the resistance between the (K40) IAC #1 Driver circuit and #2,
#3, #4 Driver circuits.
Istheresistancebelow100ohmsonanyoftheDrivers?
Ye s>>
Repair the short between the IAC Driver circuits.
Perform POWERTRAIN VERIFICATION TEST. (Refer to 9 -
ENGINE - STANDARD PROCEDURE)
No>>
Go To 3
Page 1300 of 5267
3.(K60) IAC #2 DRIVER CIRCUIT SHORTED TO (K39) IAC #3 OR (K59) IAC #4 DRIVER CIRCUITS
NOTE: The following steps are checking for a short between the
IAC Driver circuits.
Measure the resistance between the (K60) IAC #2 Driver circuit and
(K39) IAC #3, (K59) IAC #4 Driver circuits.
Istheresistancebelow100ohmsonanyoftheDrivers?
Ye s>>
Repair the shorted between the IAC Driver circuits.
Perform POWERTRAIN VERIFICATION TEST. (Refer to 9 -
ENGINE - STANDARD PROCEDURE)
No>>
Go To 4
4.(K39) IAC #3 DRIVER CIRCUIT SHORTED TO THE (K59) IAC #4 DRIVER CIRCUIT
NOTE: The following steps are checking for a short between the
Driver Circuits.
Measure the resistance between the (K39) IAC #3 Driver circuit and the
(K59) IAC #4 Driver circuit.
Istheresistancebelow100ohms?
Ye s>>
Repair the short between the IAC Driver circuits.
Perform POWERTRAIN VERIFICATION TEST. (Refer to 9 -
ENGINE - STANDARD PROCEDURE)
No>>
Go To 5
Page 1303 of 5267

P0513-INVALID SKREEM KEY
For a complete wiring diagramRefer to Section 8W.
When Monitored:
Ignition on.
Set Condition:
The Gateway detects that the Secret Key message is invalid or missing. One Trip Fault.
Possible Causes
WCM/SKREEM
POWERTRAIN CONTROL MODULE
GATEWAY MODULE
COMMUNICATION PROBLEM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.ACTIVE DTC
Ignition on, engine not running.
With the scan tool, read the Gateway Module DTCs.
Is the DTC active at this time?
Ye s>>
Go To 2
No>>
Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
2.COMMUNICATION (CAN BUS or J1850)
NOTE: For vehicle communication problems, use the scan tool to refer to theNetwork Review Screen. The
screen depicts a high level view of the vehicle network. Fault and problem areas appear in red. Selecting
any of the network components allows access to the source of the problem.
Does the scan tool display a Vehicle Network problem or NO RESPONSE condition?
Ye s>>
Refer to the appropriate BUS Communication test in the Section 8 ELECTRONIC CONTROL MODULE
- ELECTRICAL DIAGNOSTICS.
No>>
Go To 3
3.SKREEM/SKIM TROUBLE CODES SET
With the scan tool, check for SKREEM/SKIM DTCs.
Are any DTCs present in the SKREEM/SKIM?
Ye s>>
Refer to Section 8 - Electrical VEHICLE THEFT SECURITY - ELECTRICAL DIAGNOSTICS and perform
the appropriate Diagnostic Procedure.
No>>
Go To 4