Step 1: Check The Throttle Position Sensor
CAUTION:
To prevent damage to scan tool MB991502, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.
- Using scan tool MB991502.
- Connect scan tool MB991502 to the data link connector.
- Turn the ignition switch to the "ON" position.
- Read the MFI-DTC.
- Turn the ignition switch to the "LOCK" (OFF) position.
Is the MFI-DTC P0121, P0122 or P0123 is output?
- YES
See appropriate SELF DIAGNOSTICS article in ENGINE PERFORMANCE. - NO
Go to step 2 .