1. Powertrain Control Module

Turn the ignition off.

Verify that the upstream O2 Sensors harness connectors are connected to the correct O2 Sensor and repair as necessary.

Turn the ignition on.

With the DRB III(R), erase all PCM DTCs.

Turn the ignition off, then back on.

Start and let the engine idle.

If the DTC does not set right away it may be necessary to test drive the vehicle.

With the DRB III(R), read PCM DTCs.

Fig 1: Reading PCM DTC's

Courtesy of DAIMLERCHRYSLER CORP.

Did DTC P0040: 1/1 AND 2/1 O2 SENSOR HARNESS CONNECTORS REVERSED set again? 

1. Yes  >>
   NOTE: Before continuing, verify the front O2 Sensor harness connectors are connected to the correct O2 Sensor with no damage or terminal push out. Repair as necessary.

   If OK, replace and program the Powertrain Control Module. See ELECTRONIC CONTROL MODULES article.

   See POWERTRAIN VERIFICATION TEST - VER 2  .

2. No  >> Go to 2