Mazda MX-6 1998, Workshop Manual

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TROUBLESHOOTING [ENGINE CONTROL FS]
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.
p r 09-1 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 0 9 -1 4 IMMOBILIZER SYSTEM REPROGRAMMING
PROCEDURE, PCM Replacement
DTC P1622
Key ID number does not match
DESCRIPTION
• ID number stored in immobilizer unit (IU) and PCM does not match. This DTC is indicated
only after immobilizer unit is replaced and reprogramming system.
[Possible Cause]
• Unregistered key is used in step 3 of immobilizer system • Transformation of key ID number stored in PCM.
reprogram procedure (IU replacement).
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 ENGINE IS STARTING NORMALLY
USING ANOTHER REGISTERED KEY
• Does engine start with another
registered key?
Yes Previous key is defective. Discard it.
No
Replace PCM and reprogram immobilizer system.
tr 0 9 -1 4 IMMOBILIZER SYSTEM REPROGRAMMING
PROCEDURE, PCM Replacement
Note
• Do not use PCM on other vehicle for testing. Diagnostic trouble code No. P1622 will be displayed again.
DTC P1623 Code word or key ID number write/ read error in PCM
DESCRIPTION • PCM internal EEPROM damaged
[Possible Cause]
• PCM internal EEPROM damaged
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 Replace PCM and reprogram immobilizer system.
tr 0 9 -1 4 IMMOBILIZER SYSTEM REPROGRAMMING
PROCEDURE, PCM Replacement
No Different DTC displayed:
Go to appropriate DTC inspection.
No DTC displayed:
Troubleshooting is completed.
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