DTC - 11 Diagnostic Procedures

Transponder communication system or radio interference of encrypted code

Ignition Key Ring Antenna Circuit:

CIRCUIT OPERATION
The ignition key is powered by the ignition key ring antenna, and sends an encrypted code. The ignition key ring antenna receives the encrypted code, and determines whether the ignition key is a registered key or not.

DTC SET CONDITION
- If the engine is started while several ignition keys are in the vicinity, interference between the different keys may occur, which will cause this code to be generated.
- The encrypted code of the transponder is not sent to the immobilizer-ECU immediately after the ignition switch is turned to "ON" position.

NOTE: DTC 11 is always output together with MFI system DTC P1610.

TROUBLESHOOTING HINTS
- Radio interference of encrypted code
- Malfunction of transponder
- Malfunction of ignition key ring antenna
- Malfunction of immobilizer-ECU
- Damaged wiring harness of connectors

DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB991502: Scan Tool

STEP 1. Is there any other key near the key in the ignition?

YES: Move the other key well away from key being used. Confirm that diagnostic trouble code 11 is not output.
NO: Go to Step 2.

STEP 2. Does the engine start using the spare ignition key which encrypted code has been registered?

YES: replace the ignition key that does not work. Then register the password (secret code) and encrypted code. Confirm that diagnostic trouble code 11 is not output.
NO: Go to Step 3.

STEP 3. Which DTC is output, DTC 11 or 12?

DTC 12 is output: Refer to DTC 12.
DTC 11 is output: Go to Step 4.




STEP 4. Check the ignition key ring antenna by backprobing.
Do not disconnect the ignition key ring antenna connector C- 128 and check the resistance on the harness side connector between terminal number 3 and terminal number 7 by backprobing.

Q: Is the resistance less than 2 ohms?

YES: Go to Step 5.
NO: Replace the ignition key ring antenna. Confirm that diagnostic trouble code 11 is not output.







STEP 5. Check immobilizer-ECU connector C-121 and ignition key ring antenna connector C-201 for damage.

Q: Are immobilizer-ECU connector C-128 and ignition key ring antenna connector C-201 in good condition?

YES: Go to Step 6.
NO: Repair or replace them. Refer to Harness Connector Inspection. Confirm that diagnostic trouble code 11 is not output.







STEP 6. Check the harness wires between immobilizer- ECU connector C-128 and ignition key ring antenna connector C-201.

Q: Are the harness wires between immobilizer-ECU connector C-128 and ignition key ring antenna connector C-201 in good condition?

YES: replace the immobilizer-ECU. Then register the password (secret code) and encrypted code. Confirm that diagnostic trouble code 11 is not output.
NO: Repair them. Confirm that diagnostic trouble code 11 is not output.