P1243

DTC P1243: Inquiry/Response Error

TECHNICAL DESCRIPTION

Monitors the computation function of the ECM.

DTC SET CONDITIONS

Check Condition

- Ignition switch is "ON" position.
Judgment Criterion

- ECM can not calculate input data.

FAIL-SAFE AND BACKUP FUNCTION

- Microcomputer is reset.

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 DTC P1243 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.