DTC U1418, Checking for Intermittent Condition, System Checks, Component Checks: Other Jeep Compass I

Monitor Conditions

1. When Monitored: Ignition on.

Set Conditions

1. Set Condition: The PCM gets an implausible signal over the CAN C circuit from the ABS Module. The circuit is continuously monitored.

Possible Causes

Perform PRE-DIAGNOSTIC TROUBLESHOOTING PROCEDURE .

The ABS Module sends an implausible distance signal over the CAN C Bus circuit to the PCM.

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1. MECHANICAL CONDITION NOTE: Check and diagnose all the TIPM DTC(s) before continuing. NOTE: Ensure the Gear selector is in Park or Neutral. NOTE: Verify the battery is fully charged and capable of passing a load test before continuing. WARNING: Make sure the battery is disconnected, then wait two minutes before proceeding. Failure to do so may result in personal injury or possible death. Turn the engine over by hand to make sure the engine is not seized. Is the engine able to turn over? Yes Go to step 2 . No Repair the mechanical condition preventing the starter motor from cranking. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .
2. EXCESSIVE RESISTANCE IN THE BATTERY CIRCUIT Connect the battery cables. Turn the ignition off. Check the Battery Cables for excessive resistance using the service information procedure. Did either Battery Cable have a voltage drop greater than 0.2 of a volt? Yes Repair the excessive resistance in the Battery circuit. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Go to step 3 .
3. MANUAL TRANSMISSION Is this vehicle equipped with a Manual transmission? Yes Go to step 8 . No Go to step 4 .
4. START ENABLE OPERATION (ATX) Turn ignition on. Using a scan tool, monitor the Ignition Start Switch Sense. Turn the ignition switch to the crank position. Does the Ignition Start Switch Sense state change from Low to High? Yes Ensure the battery connection is clean and fastened tightly to the Starter. If OK, replace the Starter in accordance with the Service Information. No Go to step 5 .
5. START ENABLE CIRCUIT (ATX) Turn the ignition off. Disconnect the PCM harness connector. NOTE: When checking circuits at the Powertrain Control Module (PCM), be careful not to damage or distort the connector terminals. Improper measurement technique could result in poor pin to terminal contact. Using a 12-volt test light connected to ground, probe the Start Enable circuit in the PCM harness connector while holding the ignition key in the start position. Does the test light illuminate brightly? Yes Replace the PCM in accordance with the Service Information. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Go to step 6 .
6. TRANSMISSION RANGE SENSOR (ATX) Turn the ignition off. Test light still in the above position. Disconnect the Transmission Range Sensor harness connector. Using a jumper wire, connect one end to the Start Enable circuit and the other to the Fused Ignition Switch Output (Start) circuit in the Transmission Range Sensor harness connector. Turn the ignition to the crank position. Does the test light illuminate brightly? Yes Replace Transmission Range Sensor harness. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Go to step 7 .
7. FUSED IGNITION SWITCH OUTPUT (START) CIRCUIT (ATX) Turn the ignition off. Using a 12-volt test light connected to ground, probe the Fused Ignition Switch Output (Start) circuit in the Transmission Range Sensor harness connector. Turn the ignition to the crank position. Does the test light illuminate brightly? Yes Repair the Start Enable circuit. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Check the Fused Ignition Switch Output (Start) circuit for an open. If OK, replace the TIPM in accordance with the Service Information. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .
8. START ENABLE OPERATION (MTX) Turn ignition on. Using a scan tool, monitor the Ignition Start Switch Sense. Turn the ignition switch to the crank position. Does the Ignition Start Switch Sense state change from Low to High? Yes Go to step 10 . No Go to step 9 .
9. STATER ENABLE CIRCUIT (MTX) Turn the ignition off. Disconnect the PCM harness connector. NOTE: When checking circuits at the Powertrain Control Module (PCM), be careful not to damage or distort the connector terminals. Improper measurement technique could result in poor pin to terminal contact. Using a 12-volt test light connected to ground, probe the Start Enable circuit in the PCM harness connector while holding the ignition key in the start position. Does the test light illuminate brightly? Yes Replace the PCM in accordance with the Service information. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Check the Start Enable circuit. If OK, replace the TIPM in accordance with the Service Information. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .
10. CLUTCH INTERLOCK OPERATION (MTX) Turn ignition on. Using a scan tool, monitor the Clutch Switch. Press the Clutch in and out. Does Clutch Switch display Released and then Pressed? Yes Replace the Starter in accordance with the Service Information. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Go to step 11 .
11. CLUTCH INTERLOCK OPERATION (MTX) Turn the ignition off. Disconnect the PCM harness connector. NOTE: When checking circuits at the Powertrain Control Module (PCM), be careful not to damage or distort the connector terminals. Improper measurement technique could result in poor pin to terminal contact. Using a 12-volt test light connected to battery voltage, probe the Clutch interlock Signal circuit in the PCM harness connector while pressing the clutch pedal in. Does the test light illuminate brightly? Yes Replace the PCM in accordance with the Service information. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Go to step 12 .
12. CLUTCH INTERLOCK SWITCH (MTX) Turn the ignition off. Test light still in the above position. Disconnect the Clutch Interlock Switch harness connector. Using a jumper wire, connect one end to the Clutch Interlock Switch Signal circuit and the other to the Clutch Interlock Switch ground circuit in the Clutch Interlock Switch harness connector. Does the test light illuminate brightly? Yes Replace Clutch Interlock Switch. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Go to step 13 .
13. CLUTCH INTERLOCK OPERATION (MTX) Remove the jumper wire. Using a 12-volt test light connected to battery voltage, probe the Clutch Interlock Switch ground circuit. Does the test light illuminate brightly? Yes Repair the Clutch Interlock Switch ground circuit. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Repair the Clutch Interlock Switch signal circuit. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .

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1. (A931) FUSED B+ CIRCUIT (PCM) NOTE: The scan tool and cable must be operating properly for the results of this test to be valid. NOTE: Make sure the ignition switch was on while trying to communicate with the PCM. Turn the ignition off. Disconnect the C1 PCM harness connectors. NOTE: When checking circuits at the Powertrain Control Module (PCM), be careful not to damage or distort the connector terminals. Improper measurement technique could result in poor pin to terminal contact. Using a 12-volt test light connected to ground, probe the (A931) Fused B+ circuit in the PCM harness connector. NOTE: The test light should be illuminated and bright. Compared the brightness to that of a direct connection to the battery. Does the test light illuminate brightly? Yes Go to step 2 . No Repair the open or short to ground in the (A931) Fused B+ circuit. Inspect and replace fuses as necessary. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .
2. (F202) IGNITION SWITCH OUTPUT (RUN-START) CIRCUITS (PCM) Turn the ignition on. NOTE: When checking circuits at the Powertrain Control Module (PCM), be careful not to damage or distort the connector terminals. Improper measurement technique could result in poor pin to terminal contact. Using a 12-volt test light connected to ground, probe the (F202) Fused Ignition Switch Output circuit in the PCM harness connector. Turn the ignition to run. NOTE: The test light should be illuminated and bright. Compared the brightness to that of a direct connection to the battery. Does the test light illuminate brightly? Yes Go to step 3 . No Repair the (F202) Ignition Switch Output circuits. Inspect and replace fuses as necessary. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .
3. (Z925) GROUND CIRCUITS (PCM) Turn the ignition off. NOTE: When checking circuits at the Powertrain Control Module (PCM), be careful not to damage or distort the connector terminals. Improper measurement technique could result in poor pin to terminal contact. Using a 12-volt test light connected to battery voltage, probe both the (Z925) PCM ground circuits NOTE: The test light should be illuminated and bright. Compared the brightness to that of a direct connection to the battery. Does the test light illuminate brightly at both terminals? Yes Go to step 4 . No Repair the Ground circuit(s). Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .
4. (A14) FUSED B+ CIRCUIT (MAIN RELAY) Turn the ignition off. Remove the Main Relay. Using a 12-volt test light connected to ground, probe the (A14) Fused B+ circuit at the Main Relay terminal. NOTE: The test light should be illuminated and bright. Compared the brightness to that of a direct connection to the battery. Does the test light illuminate brightly? Yes Go to step 5 . No Repair the (A14) Fused B+ circuit. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .
5. (A935) FUSED B+ CIRCUIT (MAIN RELAY) Using a 12-volt test light connected to ground, probe the (A935) Fused B+ circuit at the Main Relay terminal. NOTE: The test light should be illuminated and bright. Compared the brightness to that of a direct connection to the battery. Does the test light illuminate brightly? Yes Go to step 6 . No Repair the (A935) Fused B+ circuit. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .
6. (F342) MAIN RELAY OUTPUT CIRCUITS Turn the ignition on. Using a jumper wire, jumper across the Main Relay from (K542) Main Relay Output circuit and the (A14) Fused B+ circuit. NOTE: When checking circuits at the Powertrain Control Module (PCM), be careful not to damage or distort the connector terminals. Improper measurement technique could result in poor pin to terminal contact. With a 12-volt test light connected to ground, probe the (F342) Main Relay Output circuits in the PCM harness connector. NOTE: The test light should be illuminated and bright. Compared the brightness to that of a direct connection to the battery. Does the test light illuminate brightly at both terminals? Yes Go to step 8 . No Go to step 7 .
7. (K542) MAIN RELAY OUTPUT CIRCUIT Jumper wire still installed. Disconnect the C8 TIPM harness connector. Using a 12-volt test light connected to ground, probe the (K542) Main Relay Output circuit in the TIPM harness connector. NOTE: The test light should be illuminated and bright. Compared the brightness to that of a direct connection to the battery. Does the test light illuminate brightly? Yes Repair the (K542) Main Relay Output circuit between the TIPM and the Main Relay. Inspect the related fuses. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Repair the (F342) Main Relay Output circuit(s). Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .
8. MAIN RELAY OUTPUT Turn the ignition off. Remove one end of the jumper wire. Connect the PCM harness connector. Turn the ignition on. Return the jumper wire across the Main Relay. Using a scan tool, attempt to communication with the PCM. Were you able to communication with the PCM? Yes Go to step 9 . No Go to step 11 .
9. MAIN RELAY NOTE: To continue the following test, leave the jumper wire in place with the ignition on. Using the scan tool, actuate the Main Relay. Using a 12-volt test light connected to battery voltage, probe the (K51) Main Relay Control circuit in the Main Relay connector. Does the test light illuminate and flash on and off? Yes Replace the Main Relay. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Go to step 10 .
10. (K51) MAIN RELAY CONTROL CIRCUIT Turn the ignition off. Disconnect the PCM harness connector. Disconnect the C1 PCM harness connector. NOTE: When checking circuits at the Powertrain Control Module (PCM), be careful not to damage or distort the connector terminals. Improper measurement technique could result in poor pin to terminal contact. Measure the resistance of the (K51) Main Relay Control circuit between the PCM harness connector and the Main relay connector. Is the resistance below 5.0 ohms? Yes Repair the open in the (K51) Main Relay Control circuit. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Replace and program the Powertrain Control Module per Service Information. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .
11. (D65) CAN C BUS (+) CIRCUIT OPEN Turn the ignition off. Disconnect the TIPM harness connector. NOTE: When checking circuits at the Powertrain Control Module (PCM), be careful not to damage or distort the connector terminals. Improper measurement technique could result in poor pin to terminal contact. Measure the resistance of the (D65) CAN C Bus (+) circuit between the TIPM connector and the PCM harness connector. Is the resistance below 5.0 ohms? Yes Go to step 12 . No Repair the (D65) CAN C Bus (+) circuit for an open. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .
12. (D64) CAN C BUS (-) CIRCUIT OPEN NOTE: When checking circuits at the Powertrain Control Module (PCM), be careful not to damage or distort the connector terminals. Improper measurement technique could result in poor pin to terminal contact. Measure the resistance of the (D64) CAN C Bus (-) circuit between the TIPM connector and the PCM harness connector. Is the resistance below 5.0 ohms? Yes Replace and program the Powertrain Control Module in accordance with the service information. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Repair the (D64) CAN C Bus (-) circuit for an open. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .