DTC P1602 [AJ] (VIN: JM0 LW10J300 301406-, JMZ LW69J7*# 307683-, JM8 LW28J**# 301514-, JM8 LW28A**# 301514- (Assumed))

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 64
• 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 64
• 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

Diagnostic procedure

STEP

INSPECTION

ACTION

1
VERIFY RELATED SERVICE INFORMATION AVAILABILITY
• Check for related Service Information availability.
• Is any related Service Information available?
Yes
Perform repair or diagnosis according to available Service Information.
• If vehicle is not repaired, go to next step.
No
Go to next step.
2
CLASSIFY NO DTC DETECTED OR SOME DTC DETECTED
• Clear DTC from memory using WDS or equivalent.
• Turn the ignition switch off and ON (Engine OFF).
• Has DTC P1624 been detected?
Yes
Go to step 10.
No
Go to next step.
3
INSPECT IMMOBILIZER UNIT CONNECTOR FOR POOR CONNECTION
• Turn the ignition switch off.
• Disconnect immobilizer unit connector.
• Check 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 any 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.
• Check 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
• Check continuity between coil terminal A (part-side) and body ground.
• Is there any continuity?
Yes
Replace coil, then go to Step 19.
No
Go to next step.
7
INSPECT COIL CIRCUIT FOR SHORT
• Connect coil connector.
• Check continuity between immobilizer unit terminal F (harness-side) and body ground.
• Is there any continuity?
Yes
Repair or replace harness for short circuit, then go to Step 19.
No
Go to next step.
8
INSPECT PCM CONNECTOR FOR POOR CONNECTION
• Disconnect PCM connector.
• Check 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
• Disconnect PCM connector.
• Measure continuity between immobilizer unit terminal A (harness-side) and PCM terminal 64.
• Is there any 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 COIL CONNECTOR FOR POOR CONNECTION
• Disconnect coil connector.
• Check for poor connection (damaged, pulled-out terminals, corrosion, etc.).
• Are there any malfunctions?
Yes
Repair or replace harness, then go to Step 19.
No
Go to next step.
12
INSPECT COIL FOR OPEN CIRCUIT
• Disconnect coil connector.
• Measure resistance between coil terminals (part-side).
• Is there any 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 any 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 DTC.
• Has immobilizer unit DTC 03 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 DTC.
• 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 IMMOBILIZER UNIT CONNECTOR FOR POOR CONNECTION
• Turn the ignition switch off.
• Disconnect immobilizer unit connector.
• Check for poor connection (damaged, pulled-out terminals, corrosion, etc.).
• Are there any malfunctions?
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 the ignition switch 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 TO HARNESS
• Measure resistance between immobilizer unit terminal A (harness-side) and body ground.
• Is there any 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.
• Turn the ignition switch off, then start engine.
• 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 inspection.
No
Troubleshooting completed.