DTC P1602 [L3]

BME010201600W01

DTC P1602

Immobilizer unit-PCM communication error

DETECTION CONDITION

• Command transmission from the PCM to the immobilizer unit exceeds limit.
• No response from immobilizer unit.

POSSIBLE CAUSE

• Immobilizer unit malfunction
• Coil (immobilizer system) malfunction
• Key (transponder) malfunction
• PCM malfunction
• Open circuit in wiring between immobilizer unit terminal A and PCM terminal 2Q
• Open circuit in wiring between immobilizer unit terminal C and body ground
• Open circuit in wiring between immobilizer unit terminal F and coil terminal A
• Open circuit in wiring between immobilizer unit terminal D and coil terminal C
• Short to ground circuit in wiring between immobilizer unit terminal A and PCM terminal 2Q
• Short to ground circuit in wiring between immobilizer unit terminal F and coil terminal A
• Short to ground circuit in wiring between immobilizer unit terminal D and coil terminal C
• Poor connection of immobilizer unit, PCM connector or coil
• Open circuit in wiring between immobilizer unit terminal J and battery positive terminal

Diagnostic procedure

STEP

INSPECTION

ACTION

1
PERFORM DTC CONFIRMATION PROCEDURE
• Perform DTC CONFIRMATION PROCEDURE.
• Is same DTC present?
Yes
Go to next step.
No
Intermittent concern exists. Go to INTERMITTENT CONCERN TROUBLESHOOTING procedure.
2
CLASSIFY NO DTC DETECTED OR SOME DTC DETECTED
• Clear DTC from memory using WDS or equivalent.
• Turn ignition key to OFF and ON (Engine OFF).
• Has DTC P1624 been detected?
Yes
Go to step 10.
No
Go to next step.
3
INSPECT POOR CONNECTION OF IMMOBILIZER UNIT CONNECTOR
• Turn ignition key to OFF.
• Disconnect immobilizer unit connector.
• Inspect for poor connection (damaged, pulled-out terminals, corrosion, etc.).
• Is there any malfunction?
Yes
Repair or replace terminals, then go to Step 19.
No
Go to next step.
4
INSPECT GROUND CIRCUIT OF IMMOBILIZER UNIT FOR OPEN CIRCUIT
• Measure resistance between immobilizer unit terminal C (harness-side) and body ground.
• Is there continuity?
Yes
Go to next step.
No
Repair or replace harness for open, then go to Step 19.
5
INSPECT COIL TERMINAL
• Disconnect coil connector.
• Inspect for bent terminals.
• Is there any malfunction?
Yes
Repair or replace terminals, then go to Step 19.
No
Go to next step.
6
INSPECT COIL FOR SHORT CIRCUIT
• Inspect continuity between coil terminal A (part-side) and body ground.
• Is there continuity?
Yes
Replace coil, then go to Step 19.
No
Go to next step.
7
INSPECT COIL CIRCUIT FOR SHORT
• Connect coil connector.
• Inspect continuity between immobilizer unit terminal F (harness-side) and body ground.
• Is there continuity?
Yes
Repair or replace harness for short circuit, then go to Step 19.
No
Go to next step.
8
INSPECT POOR CONNECTION OF PCM CONNECTOR
• Disconnect PCM connector.
• Inspect for poor connection (damaged, pulled-out terminals, corrosion, etc.).
• Is there any malfunction?
Yes
Repair or replace harness, then go to Step 19.
No
Go to next step.
9
INSPECT COMMUNICATION LINE FOR OPEN
• Measure continuity between immobilizer unit terminal A (harness-side) and PCM terminal 2Q.
• Is there continuity?
Yes
Go to step 19.
No
Repair or replace harness for open circuit, then go to Step 19.
10
CLASSIFY MALFUNCTION BY ANOTHER DETECTED DTCS
• Has DTC P1602 detected?
Yes
Go to Step 14.
No
Go to next step.
11
INSPECT POOR CONNECTION OF COIL CONNECTOR
• Disconnect coil connector.
• Inspect for poor connection (damaged, pulled-out terminals, corrosion, etc.).
• Is there any malfunction?
Yes
Repair or replace harness, then go to Step 19.
No
Go to next step.
12
INSPECT COIL FOR OPEN
• Disconnect coil connector.
• Measure resistance between coil terminals (part-side).
• Is there continuity?
Yes
Go to next step.
No
Replace coil, then go to Step 19.
13
INSPECT COIL CIRCUIT FOR OPEN CIRCUIT
• Connect coil connector.
• Measure the resistance between immobilizer connector F and D (harness-side).
• Is there continuity?
Yes
Go to Step 19.
No
Repair or replace harness for open circuit, then go to Step 19.
14
CLASSIFY MALFUNCTION BY ANOTHER DETECTED DTCS.
• Has immobilizer unit DTC 03 been detected?
Yes
Key has not transponder, change to registered key.
Then go to Step 19.
No
Go to next step.
15
CLASSIFY MALFUNCTION BY ANOTHER DETECTED DTCS.
• Has immobilizer unit DTC 01 detected?
Yes
Key that using for ignition is not registered.
Reprogram key or using another registered key, then go to next step.
No
Go to next step.
16
INSPECT POOR CONNECTION OF IMMOBILIZER UNIT CONNECTOR
• Turn ignition key to OFF.
• Disconnect immobilizer unit connector.
• Inspect for poor connection (damaged, pulled-out terminals, corrosion, etc.).
• Is there any malfunction?
Yes
Repair or replace harness, then go to next step.
No
Go to next step.
17
INSPECT IMMOBILIZER UNIT POWER CIRCUIT FOR OPEN CIRCUIT
• Turn ignition key to ON (Engine OFF).
• Measure voltage between immobilizer connector J (harness-side) and body ground.
• Is there voltage B+?
Yes
Go to next step.
No
Repair or replace harness for open circuit, then go to Step 19.
18
INSPECT COMMUNICATION LINE FOR SHORT HARNESS
• Measure resistance between immobilizer unit terminal A (harness-side) and body ground.
• Is there continuity?
Yes
Repair or replace harness for short, then go to next step.
No
Go to next step.
19
VERIFY TROUBLESHOOTING OF DTC P1602 COMPLETED
• Make sure to reconnect all disconnected connectors.
• Clear DTC from memory using WDS or equivalent.
• Perform KOEO self-test.
• Is same DTC present?
Yes
Replace PCM, then go to next step.
No
Go to next step.
20
VERIFY AFTER REPAIR PROCEDURE
• Perform "After Repair Procedure".
• Is there any DTC present?
Yes
Go to applicable DTC troubleshooting.
No
Troubleshooting completed.