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Home >> Chrysler >> 2003 >> Sebring Coupe V6-3.0L VIN H >> Repair and Diagnosis >> Accessories and Optional Equipment >> Antitheft and Alarm Systems >> Testing and Inspection >> Symptom Related Diagnostic Procedures >> Symptom Procedures >> Inspection Procedure 1

Inspection Procedure 1

Communication with Scan Tool MB991502 is Impossible.


Immobilizer-ECU Power Supply, Ground And ECM <M/T> Or PCM <A/T> Communication Line Circuit:









CIRCUIT OPERATION
Immobilizer-ECU is energized when the ignition switch is turned ON and the MFI relay is turned on. The ECM or PCM transmits a signal from scan tool MB991502 to the immobilize-ECU as it is. In the same way, a signal from the immobilize- ECU is also transmilled to scan tool MB991502 as it Is.

TECHNICAL DESCRIPTION (COMMENT)
- This malfunction may be caused by a defective immobilize-ECU, ECM or PCM , or a defect in the communication line between the immobilize-ECU and ECM or PCM . If this malfunction appears when the MFI system and scan tool MB991502 can communicate each other, MFI system DTC P1610 will reset.

- If the MFI system is normal, the MFI relay can be determined as normal. In addition, if the MFI system and scan tool MB991502 can communicate each other, the circuits between the data link connector and the ECM or PCM can determined as normal.

NOTE: If this malfunction appears, MFI system DTC P1610 will be set.

TROUBLESHOOTING HINTS
- Malfunction of immobilize-ECU
- Malfunction of ECM or PCM
- Damaged harness wires or connectors

DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB991502: Scan Tool (MUT-II)

STEP 1. Check scan tool MB991502 communicates with the MFI system and MFI system DTC output other than P1610.

Q: Can scan tool MB991502 communicate with the MFI system? Does MFI system DTC other than P1610 reset?

YES: Refer to MFI Diagnosis <2.4L ENGINE> or MFI Diagnosis <3.0L ENGINE>.
NO: Go to Step 2.

STEP 2. Check the immobilizer-ECU power supply circuit by backprobing.




1. Do not disconnect immobilizer-ECU connector C-128.
2. Turn the ignition switch to the ON position.




3. Measure the voltage between terminal 7 and ground by backprobing.

Q: Is the voltage approximately 12 volts (battery positive voltage)?

YES: Go to step 5.
NO: Go to step 3.







STEP 3. Check immobilizer-ECU connector C-128 and MFI relay connector A-18X for damage.

Q: Are immobilizer-ECU connector C-128 and MFI relay connector A-18X damaged?

YES: Repair or replace the connector(s). Refer to Harness Connector Inspection. Confirm that scan tool MB991 502 communicates normally.
NO: Go to step 4.







STEP 4. Check the wiring harnesses between immobilizer-ECU connector C-128 (terminal 7) and MFI relay connector A-18X (terminal 4).

NOTE: Also check the intermediate connector C-25. If intermediate connector C-25 is damaged, repair or replace the connector. Refer to Harness Connector Inspection.

Q: Are the wiring harnesses between immobilizer-ECU connector C-128 (terminal 7) and MFI relay connector A-18X (terminal 4) damaged?

YES: Replace the wiring harness(es). Confirm that scan tool MB991502 communicates normally.

NO: There is no action to be taken.

STEP 5. Check the immobilizer-ECU ground circuit by backprobing.




1. Do not disconnect immobilizer-ECU connector C-128.




2. Measure the resistance between terminal 3 and ground by backprobing.

Q: Is the resistance less than 2 ohms?

YES: Go to Step 8.
NO: Go to Step 6.




STEP 6. Check immobilizer-ECU connector C-128 for damage.

Q: Is immobilizer-ECU connector C-128 in good condition?

YES: Go to Step 7.
NO: Repair or replace the connector. Refer to Harness Connector Inspection. Confirm that scan tool MB991502 communicates normally.




STEP 7. Check the wiring harness between immobilizer-ECU connector C-128 (terminal 3) and ground.

Q: Is the wiring harness between immobilizer-ECU connector C-128 (terminal 3) and ground damaged?

YES: Repair the wiring harness. Confirm that scan tool MB991502 communicates normally.

NO: There is no action to be taken.







STEP 8. Check immobilizer-ECU connector C-128 and ECM connector C-116 <2.4L M/T>, C-122 <3.0L M/T> or PCM connector C-121 <2.4L A/T>, C-123 <3.0L A/T> for damage.

Q: Are immobilizer-ECU connector C-128 and ECM connector C-116 <2.4L M/T>, C-122 <3.0L M/T> or PCM connector C-121 <2.4L A/T>, C-123 <3.0L A/T> in good condition?

YES: Go to Step 9.
NO: Repair or replace the connector(s). Refer to Harness Connector Inspection. Confirm that scan tool MB991502 communicates normally.







STEP 9. Check the wiring harnesses between immobilizer-ECU connector C-128 (terminal 5) and ECM connector C- 116 (terminal 51) <2.4L M/T>, C-122 (terminal 98) <3.0L M/T> or PCM connector C-121 (terminal 111) <2.4L A/T>, C123 (terminal 111) <3.0L A/T>.

NOTE: Also check the intermediate connector C-25. If intermediate connector C-25 is damaged, repair or replace the connector. Refer to Harness Connector Inspection.

Q: Are the wiring harnesses between immobilizer-ECU connector C-128 (terminal 5) and ECM connector C-116 (terminal 51) <2.4L M/T>, C-122 (terminal 98) <3.0L M/T> or PCM connector C-121 (terminal 111) <2.4L A/T>, C- 123 (terminal 111) <3.0L A/T> damaged?

YES: Repair the wiring harness(es). Confirm that scan tool MB991502 communicates normally.
NO: Go to Step 10.

STEP 10. Replace the immobilizer-ECU.
Replace the immobilizer-ECU.

Q: Did the communication with scan tool MB991502 become possible after replacing the immobilizer-ECU?

YES: Register the password (secret code) and encrypted code Confirm that scan tool MB991502 communicates normally.
NO: Go to Step 11.

STEP 11. Retest the system.

Q: Is a malfunction eliminated?

YES: The procedure is complete.
NO: Replace the ECM or PCM .
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