5.(C918) A/C PRESSURE SIGNAL CIRCUIT SHORTED TO THE (F855) 5-VOLT SUPPLY CIRCUIT
Measure the resistance between the (C918) A/C Pressure Signal circuit
and the (F855) 5-volt Supply circuit in the A/C Pressure Sensor harness
connector.
Is the resistance below 5.0 ohms?
Ye s>>
Repair the short between the (F855) 5-volt Supply circuit
and the (C918) A/C Pressure Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 6
6.(K900) SENSOR GROUND CIRCUIT OPEN
Measure the resistance of the (K900) Sensor ground circuit from the
A/C Pressure Sensor harness connector to the PCM harness connector.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 7
No>>
Repair the open in the (K900) Sensor ground circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
7.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 the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
P1599-A/C PRESSURE SENSOR VOLTAGE TOO LOW
For a complete wiring diagramRefer to Section 8W.
When Monitored:
With the engine running and the A/C Relay energized.
Set Condition:
The A/C Pressure Transducer Signal voltage at the PCM goes below 0.58 voltsfor 2.6 seconds.
Possible Causes
(F855) 5-VOLT SUPPLY CIRCUIT OPEN
(F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND
A/C PRESSURE SENSOR
(C918) A/C PRESSURE SIGNAL CIRCUIT SHORTED TO GROUND
(C918) A/C PRESSURE SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.A/C PRESSURE SENSORr VOLTAGE BELOW 0.6 VOLTS
NOTE: Make sure the A/C refrigerant System is properly charged per the Service Information.
Ignition on, engine not running.
With the scan tool, read DTCs and record the related Freeze Frame data.
Start the engine.
With the scan tool, read the A/C Pressure Transducer voltage.
Is the voltage below 0.60 of a volt?
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.(F855) 5-VOLT SUPPLY CIRCUIT
Turn the ignition off.
Disconnect the A/C Pressure Transducer harness connector.
Ignition on, engine not running.
Measure the voltage on the (F855) 5-volt Supply circuit in the A/C Pres-
sure Transducer harness connector.
Is the voltage between 4.5 to 5.2 volts?
Ye s>>
Go To 3
No>>
Go To 6
3.A/C PRESSURE TRANSDUCER
With the scan tool, monitor the A/C Pressure Transducer voltage with the Transducer disconnected.
Is the voltage above 0.6 of a volt?
Ye s>>
Replace the A/C Pressure Transducer.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 4
4.(C918) A/C PRESSURE SIGNAL CIRCUIT SHORTED TO GROUND
Turn the ignition off.
Disconnect the PCM harness connectors.
Measure the resistance between ground and the (C918) A/C Pressure
Signal circuit in the A/C Pressure Transducer harness connector.
Istheresistancebelow100ohms?
Ye s>>
Repair the short to ground in the (C918) A/C Pressure Sig-
nal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 5
5.(C918) A/C PRESSURE SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT
Measure the resistance between the (C918) A/C Pressure Signal circuit
and the (K900) Sensor ground circuit in the A/C Pressure Transducer
harness connector.
Istheresistancebelow100ohms?
Ye s>>
Repair the short between the (K900) Sensor ground and the
(C918) A/C Pressure Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 8
When Monitored:
With the ignition key on and the engine running over 1500 RPM after 25 seconds.
Set Condition:
When the PCM regulates the generator field and there are no detected field problems, but the voltage output
does not increase.
Possible Causes
BATTERY TEMPERATURE SENSOR
RESISTANCE IN THE BATTERY POSITIVE CIRCUIT
(K125) GENERATOR FIELD SOURCE CIRCUIT OPEN
RESISTANCE IN THE GENERATOR GROUND
(K125) GENERATOR FIELD SOURCE CIRCUIT SHORTED TO GROUND
(K20) GENERATOR FIELD CONTROL CIRCUIT OPEN
RESISTANCE IN THE GENERATOR FIELD COIL
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.CHARGING VOLTAGE BELOW 15.1 VOLTS
Turn the ignition off.
NOTE: Battery must be fully charged and capable of passing a battery load test.
NOTE: Generator Belt tension and condition must be checked before continuing.
NOTE: Inspect the vehicle for any aftermarket accessories that may exceedthe maximum Generator output.
WARNING: When the engine is operating, do not stand in direct line of the fan. Do not put your hands near
the pulley, belts, or fan. Do no wear loose clothing.
Start the engine.
Record all DTCs and the related Freeze Frame data.
With the scan tool, read the target charging voltage.
Is the target charging voltage above 15.1 volts?
Ye s>>
Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 2
2.BATTERY TEMPERATURE SENSOR
Turn the ignition off.
NOTE: Generator Belt tension and condition must be checked before continuing.
Start the engine.
Allow the engine to reach normal operating temperature.
With the scan tool in sensors, read the Battery Temp Sensor value.
Using a Thermometer, measure under hood temperature.
Is the temperature within 10° F of Battery temperature?
Ye s>>
Go To 3
No>>
Replace the Battery Temperature Sensor.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
POWERTRAIN VERIFICATION TEST
For a complete wiring diagramRefer to Section 8W.
Diagnostic Test
1.SELECTING THE PROPER VERIFICATION TEST
The following verification test are for different repairs. Select the appropriate Verification test for the
repair that has been completed.
Speed Control repair
Go To 2
Charging System repair
Go To 3
NVLD System repair
Go To 4
All other repairs
Go To 5
2.POWERTRAIN VERIFICATION TEST 1
NOTE: 1. If this vehicle is equipped with an Electronic Throttle Control system, and the APP Sensors, PCM,
or Throttle Body Assembly have been replaced, use the scan tool to perform the ETC RELEARN function.
NOTE: 2. After completing the Powertrain Verification Test the Transmission Verification Test must be per-
formed.
NOTE: 3. If the PCM has been replaced and the correct VIN and mileage have notbeen programmed, a DTC
will set in the ABS Module, Airbag Module and the SKIM/SKREEM.
NOTE: 4. If the vehicle is equipped with a Sentry Key Remote Entry, Secret Key data must be updated. Refer
to the Service Information for the PCM, SKIM/SKREEM and the Transponder (ignition key) for programming
information. Using the scan tool, program the Secret Key information intothe PCM using the PCM replaced
function under the WCM menu.
5. Inspect the vehicle to make sure that all engine components are properlyinstalled and connected.
6. Connect the scan tool to the data link connector and erase all codes.
7. Turn the speed control ON (if equipped, cruise light will be on).
8. Depress and release the SET Switch when the vehicle speed is greater than35 MPH. The speed control should
engage and hold the selected speed.
9. Press and hold the RESUME/ACCEL Switch. The vehicle speed should increase by at least 2 MPH.
10. Press and hold the COAST switch. The vehicle speed should decrease.
11. Using caution, press and release the brake pedal. The speed control should disengage.
12. Bring the vehicle speed back up to 35 MPH.
13. Press the RESUME/ACCEL switch. The speed control should resume the previously set speed.
14. Hold down the SET switch. The vehicle should decelerate.
15. Make sure vehicle speed is greater than 35 mph and release the SET Switch. The vehicle should adjust and set
a new vehicle speed.
16. Press and release the CANCEL switch. The speed control should disengage.
17. Bring the vehicle speed back up above 35 mph and engage speed control.
18. Turn the Speed Control Off. (Cruise light will be off). The speed control should disengage.
NOTE: OVERSHOOT/UNDERSHOOT FOLLOWING SPEED CONTROL SET.
19. If the vehicle operator repeatedly presses and releases the SET buttonwith their foot off of the accelerator
(referred to as
lift foot set), the vehicle may accelerate and exceed the desired set speed by up to 5 mph (8km/h).
20. It may also decelerate to less than the desired set speed, before finally achieving the desired set speed.
21. The Speed Control System has an adaptive strategy that compensates forvehicle-to-vehicle variations in speed
control cable lengths.
22. When the speed control is set with the vehicles operators foot off of theaccelerator pedal, the speed control
thinks there is excessive speed control cable slack and adapts accordingly.
23. If thelift foot setsare continually used, a speed control overshoot/undershoot condition will develop.
24. To
unlearnthe overshoot/undershoot condition, the vehicle operator has to press and release the set button
while maintaining the desired set speedusing the accelerator pedal (not decelerating or accelerating).
25. Then turn the cruise control switch to the OFF position (or press the CANCEL button if equipped) after waiting
10 seconds.
26. This procedure must be performed approximately 10-15 times to completely unlearn the overshoot/undershoot
condition.
Did the Speed Control pass the above test?
Ye s>>
Repair is complete.
No>>
Check for any related Technical Service Bulletins and/or refer to the appropriate Diagnostic Procedure.
3.POWERTRAIN VERIFICATION TEST 2
1. If this vehicle is equipped with an Electronic Throttle Control system,and the APP Sensors, PCM, or Throttle
Body Assembly has been replaced use a scan tool to perform the ETC RELEARN function.
NOTE: 2. After completing the Powertrain Verification Test the Transmission Verification Test must be per-
formed.
NOTE: 3. If the PCM has been replaced and the correct VIN and mileage have notbeen programmed, a DTC
will set in the ABS Module, Airbag Module and the SKIM/SKREEM.
NOTE: 4. If the vehicle is equipped with a Sentry Key Remote Entry, Secret Key data must be updated. Refer
to the Service Information for the PCM, SKIM/SKREEM and the Transponder (ignition key) for programming
information. Using the scan tool, program the Secret Key information intothe PCM using the PCM replaced
function under the WCM menu.
5. Inspect the vehicle to make sure that all components related to the repair are properly installed and connected.
6. With the scan tool, clear DTCs.
7. Perform generator output test. Refer to the appropriate service information as necessary.
8. Start the engine and set engine speed to 2000 RPM for at least thirty seconds.
9. Cycle the ignition key off and on.
10. With the scan tool, read the DTCs.
Are any DTCs or symptoms remaining?
Ye s>>
Check for any Technical Service Bulletins and/or refer to the appropriateDiagnostic Procedure.
No>>
Repair is complete.
4.POWERTRAIN VERIFICATION TEST 3
1. Install the Miller Tool #8404 Evaporative Emission Leak Detector (EELD) according to the instructions in the pre-
vious DTC table.
2. Set the smoke/air control switch to AIR.
3. Insert the tester’s AIR supply tip (clear hose) into the appropriate calibration orifice on the tester’s control panel
(based on DTC leak size).
4. Press the remote smoke/air start button.
5. Position the red flag on the air flow meter so it is aligned with the indicator ball.
6. When the calibration is complete, release the remote button. The EELD flow meter is now calibrated in liters per
minute to the size of leak indicated by the DTC set in the PCM.
7. Install the service port adapter #8404-14 on the vehicle’s service port.
8. Connect the Air supply hose from the EELD to the vehicle.
9. Press the remote button to activate AIR flow.
NOTE: 10. Larger volume fuel tanks, lower fuel levels or if the vehicle is equipped with a Flow Management
Valve may indicate high flow and will require 4 to 5 minutes to fill.
11. Compare the flow meter indicator ball reading to the red flag.
12. ABOVE the red flag indicates a leak present.
13. BELOW the red flag indicates a sealed system.
NOTE: If this vehicle is equipped with an Electronic Throttle Control system, and the APP Sensors, PCM, or
Throttle Body Assembly have been replaced, use the scan tool to perform theETC RELEARN function.
14. If the indicator ball shows a leak present, perform the smoke test indicated in the previous test and identify the
leak and repair. Perform this verification test when the repair is complete.
Didtheindicatorballindicatethealeakispresent?
Ye s>>
Repeat the DTC test to identify the leak and repair.
No>>
Repair is complete.
5.POWERTRAIN VERIFICATION TEST 4
NOTE: 1. After completing the Powertrain Verification Test the Transmission Verification Test must be per-
formed.
NOTE: 2. If the PCM has been replaced and the correct VIN and mileage have notbeen programmed, a DTC
will set in the ABS Module, Airbag Module and the SKIM/SKREEM.
NOTE: 3. If the vehicle is equipped with a Sentry Key Remote Entry, Secret Key data must be updated. Refer
to the Service Information for the PCM, SKIM/SKREEM and the Transponder (ignition key) for programming
information. Using the scan tool, program the Secret Key information intothe PCM using the PCM replaced
function under the WCM menu.
NOTE: 4. If this vehicle is equipped with an Electronic Throttle Control system, and the APP Sensors, PCM,
or Throttle Body Assembly have been replaced, use the scan tool to perform the ETC RELEARN function.
NOTE: 5. When replacing an O2 Sensor, the PCM RAM memory must be cleared, either by disconnecting the
PCM C1 connector or momentarily disconnecting the Battery negative terminal.
6. The NGC learns the characteristics of each O2 heater element and these old values should be cleared when
installing a new O2 sensor. The customermay experience driveability issues if this is not performed.
7. Inspect the vehicle to make sure that all engine components are properlyinstalled and connected. Reassemble
and reconnect components as necessary.
8. Connect the scan tool to the data link connector.
9. Make sure the fuel tank has at least a quarter tank of fuel. Turn off all accessories.
10. If the Catalyst was replaced, with the scan tool go to the MiscellaneousMenu Option
Catalyst Replacedand
press enter.
11. If a Comprehensive Component DTC was repaired, perform steps 12 - 14. Ifa Major OBDII Monitor DTC was
repaired skip those steps and continue verification.
12. After the ignition has been off for at least 10 seconds, restart the vehicle and run 2 minutes.
13. With the scan tool, monitor the appropriate pre-test enabling conditions until all conditions have been met. Once
the conditions have been met, switch screen to the appropriate OBDII monitor, (Audible beeps when the monitor is
running).
14. If the repaired OBDII trouble code has reset or was seen in the monitor while on the road test, the repair is not
complete. Check for any related technical service bulletins or flash updates and return to Engine Electrical Diag-
nostic List.
15. If the conditions cannot be duplicated, erase all DTCs with the Scan tool.
16. If another DTC has set, return to the Engine Electrical Diagnostic Listand follow the path specified for that DTC.
Did the OBDII Monitor run successfully and has the Good Trip Counter changed to one or more?
Ye s>>
Repair is complete.
No>>
Check for any related Technical Service Bulletins and/or refer to the appropriate Diagnostic Procedure.