Ignition System - Electrical Diagnostics: Other Jeep Commander I

Monitor Conditions

1. When Monitored: Anytime the ignition input is compared against the CAN B Bus ignition status message.

Set Conditions

1. Set Condition: The Front Control Module will set this DTC if the CAN bus message and the hardwired ignition circuit do not match.

Possible Causes

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1. 1) CHECK FOR ACTIVE DTC NOTE: If B2104 or B2105 are active, perform those tests first before proceeding. NOTE: Check the Junction Block Fuse #24. An open fuse can cause this DTC to set. If open refer to the wiring diagrams to help isolate a possible shorted circuit. With the scan tool, read the active DTC's. Cycle the ignition switch from off to on, leaving the ignition on for a minimum of 10 seconds. With the scan tool, read the active DTC's. Does the scan tool display this DTC as active? Yes Go to 2) . No If the DTC is stored, check for an intermittent condition. Using the wiring diagram/schematic as a guide, visually inspect the related wiring harness connectors. Look for broken, bent, pushed out, or corroded terminals.
2. 2) (F942) FUSED IGNITION SWITCH OUTPUT CIRCUIT OPEN Turn the ignition off. Disconnect the IPM C2 connector. Turn the ignition on. Measure the voltage of the (F942) Fused Ignition Switch Output circuit in the IPM C2 connector. Is the voltage above 10.0 volts? Yes Go to 3) . No Repair the (F942) Fused Ignition Switch Output circuit for an open. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) .
3. 3) (F942) FUSED IGNITION SWITCH OUTPUT CIRCUIT OPEN Turn the ignition off. Remove the FCM from the Integrated Power Module. NOTE: Reconnect the IPM C2 connector. Turn the ignition on. Measure the voltage of the (F942) Fused Ignition Switch Output circuit in the Front Control IPM connector. Is the voltage above 10.0 volts? Yes Replace and program the Front Control Module in accordance with the service information. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) . No Replace the Integrated Power Module in accordance with service information. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) .

1. When Monitored: With the ignition on.

1. Set Condition: The Front Control Module will set this DTC within 500ms if the (P305) Accessory Delay Relay Control circuit is open or shorted to ground.

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1. 1) CHECK FOR ACTIVE DTC With the scan tool, read the active DTC's. Cycle the ignition switch from off to on, leaving the ignition on for a minimum of 90 seconds. With the scan tool, read the active DTC's. Does the scan tool display this DTC as active? Yes Go to 2) . No If the DTC is stored, check for an intermittent condition. Visually inspect the related wiring harness connectors. Look for broken, bent, pushed out, or corroded terminals.
2. 2) RUN/ACCESSORY DELAY RELAY Turn the ignition off. Install a substitute relay in place of the original Run/Accessory Delay Relay. Cycle the ignition switch from off to on, leaving the ignition on for a minimum of 90 seconds. With the scan tool, read the active FCM DTC's. Does the scan tool display this DTC as active? Yes Go to 3) . No Replace the original Run/Accessory Delay Relay. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) .
3. 3) (P305) ACCESSORY DELAY RELAY CONTROL CIRCUIT OPEN Turn the ignition off. Remove the FCM from the Integrated Power Module. Remove the Run/Accessory Delay Relay from the Junction Block. Measure the resistance of the (P305) Accessory Delay Relay Control circuit from the Front Control Module IPM connector to the Relay connector. Is the resistance below 10.0 ohms? Yes Go to 4) . No Repair the (P305) Accessory Delay Relay Control circuit for an open. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) .
4. 4) (P305) ACCESSORY DELAY RELAY CONTROL CIRCUIT SHORTED TO GROUND Measure the resistance between ground and the (P305) Accessory Delay Relay Control circuit at the relay cavity (85). Is the resistance below 100.0 ohms? Yes Repair the (P305) Accessory Delay Relay Control circuit for a short to ground. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) . No Inspect the wiring and connectors for damage or shorted circuits. If OK, replace and program the Front Control Module in accordance with the service information. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) .

1. When Monitored: With the ignition on.

1. Set Condition: The Front Control Module will set this DTC within 500ms if the (P305) Accessory Delay Relay Control circuit is shorted to voltage.

Scheme 12

1. 1) CHECK FOR ACTIVE DTC With the scan tool, read the active DTC's. Cycle the ignition switch from off to on, leaving the ignition on for a minimum of 90 seconds. With the scan tool, read the active DTC's. Does the scan tool display this DTC as active? Yes Go to 2) . No If the DTC is stored, check for an intermittent condition. Visually inspect the related wiring harness connectors. Look for broken, bent, pushed out, or corroded terminals.
2. 2) RUN/ACCESSORY DELAY RELAY Turn the ignition off. Install a substitute relay in place of the original Run/Accessory Delay Relay. Cycle the ignition switch from off to on, leaving the ignition on for a minimum of 90 seconds. With the scan tool, read the active FCM DTC's. Does the scan tool display this DTC as active? Yes Go to 3) . No Replace the original Run/Accessory Delay Relay. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) .
3. 3) (P305) ACCESSORY DELAY RELAY CONTROL CIRCUIT SHORTED TO VOLTAGE Turn the ignition off. Remove the FCM from the Integrated Power Module. Remove the Run/Accessory Delay Relay from the Junction Block. Turn the ignition on. Measure the voltage of the (P305) Accessory Delay Relay Control circuit at the relay connector (cavity 85). Is there any voltage present? Yes Repair the (P305) Accessory Delay Relay Control circuit for a short to voltage. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) . No Inspect the wiring and connectors for damage or shorted circuits. If OK, replace and program the Front Control Module in accordance with the service information. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) .

1. When Monitored: With the ignition on.

1. Set Condition: The Front Control Module will set this DTC within 500ms if the (P305) Accessory Delay Relay Control circuit is open.

1. When Monitored: With the ignition on.

1. Set Condition: The Front Control Module will set this DTC within 500ms if the (F921) or (F923) run relay control circuit voltage is open or shorted to ground.

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1. 1) CHECK FOR ACTIVE DTC With the scan tool, read the active DTC's. Cycle the ignition switch from off to on, leaving the ignition on for a minimum of 90 seconds. With the scan tool, read the active DTC's. Does the scan tool display this DTC as active? Yes Go to 2) . No If the DTC is stored, check for an intermittent condition. Visually inspect the related wiring harness connectors. Look for broken, bent, pushed out, or corroded terminals.
2. 2) RUN RELAY Turn the ignition off. Install a substitute run relay in place of the original run relay. Cycle the ignition switch from off to on, leaving the ignition on for a minimum of 90 seconds. With the scan tool, read the active FCM DTC's. Does the scan tool display this DTC as active? Yes Go to 3) . No Replace the original run relay. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) .
3. 3) (F921) or (F923) RUN RELAY CONTROL CIRCUIT OPEN Turn the ignition off. Remove the FCM from the Power Distribution Module. Remove the run relay from the Rear Power Distribution Module. NOTE: This circuit contains a diode. When checking resistance of this circuit the red ohmmeter lead must be connected to the run relay cavity (85) and the black ohmmeter lead must be connected to the FCM-PDM connector. Measure the resistance of the Run Relay Control circuit. Is the resistance below 10.0 ohms? Yes Go to 4) . No Repair the Run Relay Control circuit for an open. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) .
4. 4) (F921) RUN RELAY CONTROL CIRCUIT SHORTED TO GROUND NOTE: This circuit contains a diode. When checking for a short to ground you must check both sides of the diode. Measure the resistance between ground and the (F921) Run Relay Control circuit at the run relay cavity (85). Is the resistance below 10.0 ohms? Yes Repair the (F921) Run Relay Control circuit for a short to ground. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) . No Go to 5) .
5. 5) (F923) RUN RELAY CONTROL CIRCUIT SHORTED TO GROUND NOTE: This circuit contains a diode. When checking for a short to ground you must check both sides of the diode. Measure the resistance between ground and the (F923) Run Relay Control circuit at the FCM-PDM connector. Is the resistance below 10.0 ohms? Yes Repair the (F923) Run Relay Control circuit for a short to ground. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) . No Inspect the wiring and connectors for damage or shorted circuits. If OK, replace and program the Front Control Module in accordance with the service information. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) .

1. When Monitored: With the ignition on.

1. Set Condition: The Front Control Module is not configured correctly setting a false DTC that does not apply to this vehicle.

1. When Monitored: With the ignition on.

1. Set Condition: The Front Control Module is not configured correctly setting a false DTC that does not apply to this vehicle.

1. When Monitored: With the ignition on.

1. Set Condition: The Front Control Module is not configured correctly setting a false DTC that does not apply to this vehicle.

1. When Monitored: With the ignition on.

1. Set Condition: The Front Control Module is not configured correctly setting a false DTC that does not apply to this vehicle.

1. When Monitored: With the ignition on.

1. Set Condition: The Front Control Module is not configured correctly setting a false DTC that does not apply to this vehicle.

1. When Monitored: With the ignition on.

1. Set Condition: The Front Control Module is not configured correctly setting a false DTC that does not apply to this vehicle.

1. When Monitored: With the ignition on.

1. Set Condition: The Front Control Module is not configured correctly setting a false DTC that does not apply to this vehicle.

1. When Monitored: With the ignition on.

1. Set Condition: The Front Control Module is not configured correctly setting a false DTC that does not apply to this vehicle.

1. When Monitored: With the ignition on.

1. Set Condition: The Front Control Module will set this DTC within 500ms if the (F1) fused ignition switch output circuit voltage is less than the expected value.

1. When Monitored: With the ignition on or off and with the FCM awake.

1. Set Condition: The Front Control Module will set this DTC within 2 seconds if the ignition unlock run/start circuit voltage is not what the expected value should be.

The (F942) Fused Ignition Switch Output circuit supplies the FCM with battery power. The FCM processes the input and sends it out as the (F1) Fused Ignition Switch Output circuit to the Shift Lever assembly (3.7L) or the PCM (except 3.7L).

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1. 1) CHECK FOR ACTIVE DTC With the scan tool, read the active DTC's. Cycle the ignition switch from off to on, leaving the ignition on for a minimum of 10 seconds then turn the ignition off. With the scan tool, read the active DTC's. Does the scan tool display this DTC as active? Yes Go to 2) . No If the DTC is stored, check for an intermittent condition. Using the wiring diagram/schematic as a guide, visually inspect the related wiring harness connectors. Look for broken, bent, pushed out, or corroded terminals.
2. 2) DETERMINE ENGINE SIZE Is this vehicle equipped with a 3.7L engine? Yes Go to 3) . No Go to 6) .
3. 3) (F1) FUSED IGNITION SWITCH OUTPUT (RUN START) CIRCUIT SHORTED TO VOLTAGE Disconnect the Shift Lever Assembly harness connector. Cycle the ignition switch from off to on then back to off. NOTE: The ignition switch must be in the off position when performing the following step. Using a 12-volt test light connected to ground, check the (F1) Fused Ignition Switch Output (Run Start) circuit. Does the test light illuminate brightly? Yes Repair the (F1) Fused Ignition Switch Output (Run Start) circuit for a short to voltage. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) . No Go to 4) .
4. 4) SHIFT LEVER ASSEMBLY Turn the ignition on. With the test light still connected from the previous step, check the (F1) Fused Ignition Switch Output (Run Start) circuit. Does the test light illuminate brightly? Yes Replace the Shift Lever Assembly in accordance with the service information. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) . No Go to 5) .
5. 5) (F1) FUSED IGNITION SWITCH OUTPUT (RUN START) CIRCUIT OPEN Turn the ignition off. Remove the FCM from the Integrated Power Module. Measure the resistance of the (F1) Fused Ignition Switch Output (Run Start) circuit between the Shift Lever Assembly and the FCM-IPM connector. Is the resistance below 5.0 ohms? Yes Inspect the wiring and connectors for damage or shorted circuits. If OK, replace and program the Front Control Module in accordance with the service information. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) . No Repair the (F1) Fused Ignition Switch Output (Run Start) circuit for an open. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) .
6. 6) (F1) FUSED IGNITION SWITCH OUTPUT (RUN START) CIRCUIT SHORTED TO VOLTAGE Disconnect the Powertrain Control Module C1 harness connector. CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis. Cycle the ignition switch from off to on then back to off. NOTE: The ignition switch must be in the off position when performing the following step. Using a 12-volt test light connected to ground, check the (F1) Fused Ignition Switch Output (Run Start) circuit. Does the test light illuminate brightly? Yes Repair the (F1) Fused Ignition Switch Output (Run Start) circuit for a short to voltage. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) . No Go to 7) .
7. 7) POWERTRAIN CONTROL MODULE Turn the ignition on. With the test light still connected from the previous step, check the (F1) Fused Ignition Switch Output (Run Start) circuit. CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis. Does the test light illuminate brightly? Yes Replace the Powertrain Control Module in accordance with the service information. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) . No Go to 8) .
8. 8) (F1) FUSED IGNITION SWITCH OUTPUT (RUN START) CIRCUIT OPEN Turn the ignition off. Remove the FCM from the Integrated Power Module. CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis. Measure the resistance of the (F1) Fused Ignition Switch Output (Run Start) circuit between the Powertrain Control Module C1 connector and the FCM-IPM connector. Is the resistance below 5.0 ohms? Yes Inspect the wiring and connectors for damage or shorted circuits. If OK, replace and program the Front Control Module in accordance with the service information. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) . No Repair the (F1) Fused Ignition Switch Output (Run Start) circuit for an open. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) .