Mazda MX-6 1998, Workshop Manual

Page: 1028 / 1282

TROUBLESHOOTING [IMMOBILIZER SYSTEM]
STEP
INSPECTION ACTION
5 CHECK WIRING HARNESS OPEN CIRCUIT
• Check for wiring harness open circuit with IU
connector disconnected:
• IU (A) - PCM (5)
• IU (C) - Ground
• IU (J) - Battery
• IU (L) - Ignition switch (black/white)
• Is there open circuit?
Yes Repair wiring harness.
No Go to next step.
6
CHECK WIRING HARNESS SHORT CIRCUIT
• Check for wiring harness short circuit with IU
connector disconnected:
• IU (A) - PCM (5)
• IU (F) - Coil (yellow)
• IU (D) - Coil (green)
• Is there short circuit?
Yes Repair wiring harness.
No Replace IU and reprogram immobilizer system.
i
tr
0 9 -1 4 IMMOBILIZER SYSTEM REPROGRAMMING
PROCEDURE, Immobilizer Replacement
Go to next step.
7
CHECK DTC REPRESENT
• Does engine start after replacing IU and
clearing DTC?
Yes Troubleshooting is completed.
No Replace PCM and reprogram immobilizer system.
c r 09-1 4 IMMOBILIZER SYSTEM REPROGRAMMING
PROCEDURE, PCM Replacement
DTC P1603
P1604
Code word unregistered in PCM
Key ID numbers unregistered in PCM
DESCRIPTION
• Code word is not registered in PCM. (P1603)
• Key ID numbers are not registered in PCM. (P1604)
[Possible Cause]
• Immobilizer system reprogram procedure was not
performed correctly after replacing PCM.
STEP INSPECTION ACTION
1 CHECK DTC PRESENT
• RESET PCM to completely clear DTCs.
tr After Repair Procedure
• RERUN OBD test.
• Is same DTC present after cranking?
Yes Perform reprogram procedure again.
e r 0 9-14 IMMOBILIZER SYSTEM REPROGRAMMING
PROCEDURE, PCM Replacement
No Troubleshooting is completed.
DTC P1621 Code word does not match after engine cranking
DESCRIPTION • Code word stored in PCM and Immobilizer unit does not match.
[Possible Cause]
• Transformation of code word stored in Immobilizer unit. • Transformation of code word stored in PCM.
STEP
INSPECTION
ACTION
1 CHECK DTC PRESENT
• RESET PCM to completely clear DTCs.
tr After Repair Procedure
• RERUN OBD test.
• Is same DTC present after cranking?
Yes Go to next step.
No Different DTC displayed:
Go to appropriate DTC inspection.
No DTC displayed:
Troubleshooting is completed.
2 CHECK DTC P1602 PRESENT
• Does P1602 present?
Yes
Go to DTC P1603 inspection.
No Replace IU and reprogram immobilizer system.
tr
0 9 -1 4 IMMOBILIZER SYSTEM REPROGRAMMING
PROCEDURE, Immobilizer Replacement
Go to next step.
3
CHECK DTC REPRESENT
• Does engine start after replacing IU and
clearing DTC?
Yes
Troubleshooting is completed.
No
Replace PCM and reprogram immobilizer system.
tr
09-1 4 IMMOBILIZER SYSTEM REPROGRAMMING
PROCEDURE, PCM Replacement
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