DTC B1702: Reception Error Of Encrypted Code: Diagnosis
Required Special Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A
- STEP 1. Check for presence of other key or things that interferes communication (such as magnets and equipment that generates radio waves) near the key in the ignition.
Q: Is there any other key near the key in the ignition?
- YES: Move the other key or things that interferes communication (such as magnets and equipment that generates radio waves) well away from key being used. Retest the system.
- NO: Go to Step 2.
- STEP 2. Check that the engine starts using the spare ignition key which encrypted code has been registered.
Q: Does the engine start using the spare ignition key for which the encrypted code has been registered?
- YES: Replace the ignition key and then register the ID codes again (Refer to ENCRYPTED CODE REGISTRATION CRITERIA TABLE ). Retest the system.
- NO: Go to Step 3.
- STEP 3. Recheck for diagnostic trouble code. CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
- Connect scan tool MB991958 to the data link connector.
- Turn the ignition switch to the "ON" position.
- Use scan tool MB991958 to check immobilizer system diagnostic trouble codes.
- Turn the ignition switch to "LOCK" (OFF) position.
- Disconnect scan tool MB991958.
Q: Which DTC is set, DTC B1702 or B1703?
- DTC B1703 is set : Refer to DTC B1703 .
- DTC B1702 is set : Go to Step 4.
- STEP 4. Check the key reminder switch (ignition key ring antenna).
- Disconnect the key reminder switch (ignition key ring antenna) connector C-310.
- Measure the resistance value between terminal number 3 and terminal number 7.
- The measured value should be 7.65 - 9.35 ohm.
Q: Is the check result normal?
- YES: Go to Step 5.
- NO: Replace the key reminder switch (ignition key ring antenna). Retest the system.
- STEP 5. Check ETACS-ECU connector C-218 and key reminder switch (ignition key ring antenna) connector C-310 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Q: Are ETACS-ECU connector C-218 and key reminder switch (ignition key ring antenna) connector C-310 in good condition?
- YES: Go to Step 6.
- NO: Repair or replace the damage component(s). Confirm that scan tool MB991958 communicates normally.
- STEP 6. Check the wiring harness between ETACS-ECU connector C-218 (terminal 57 and 58) and key reminder switch (ignition key ring antenna) connector C-310 (terminal 3 and 7).
Q: Are the wiring harness between ETACS-ECU connector C-218 (terminal 57 and 58) and key reminder switch (ignition key ring antenna) connector C-310 (terminal 3 and 7) in good condition?
- YES: Replace the ETACS-ECU and register the ID codes again (Refer to ENCRYPTED CODE REGISTRATION CRITERIA TABLE ). Retest the system.
- NO: Repair or replace the damaged component(s). Confirm that scan tool MB991958 communicates normally.