P1242

DTC P1242: Fail Safe Control Monitor

TECHNICAL DESCRIPTION

Monitors the engine speed during fail-safe control.

DTC SET CONDITIONS

Check Condition

- During fail safe control.
Judgment Criterion

- The engine speed is higher than assumed.

FAIL-SAFE AND BACKUP FUNCTION

- Throttle opening degree position is in default position.

TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)

- ECM failed.

DIAGNOSIS

Required Special Tools:

- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991910: Main Harness A

STEP 1. Using scan tool MB991958, read the diagnostic trouble code (DTC).





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.

(1)Connect scan tool MB991958 to the data link connector.
(2)Turn the ignition switch to the "ON" position.
(3)Read the DTC.
(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the diagnostic trouble code other than P1242 set?

YES Refer to, Diagnostic Trouble Code Chart Multiport Fuel Injection (MFI).

NO Go to Step 2 .

STEP 2. Using scan tool MB991958, read the diagnostic trouble code
(DTC).

(1)Turn the ignition switch to the "ON" position.

(2)After the DTC has been deleted, read the DTC again.

(3)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is DTC P1242 set?

YES Replace the ECM (Refer to, Removal and Installation Removal and Replacement).
NO It can be assumed that this malfunction is intermittent. How to Cope With Intermittent Malfunctions.