5. O2 Heater Control Circuit Open

Turn the ignition off.

Disconnect the PCM harness connectors.

NOTE: Check connectors - Clean/repair as necessary.

Measure the resistance of the O2 Heater Control circuit from the O2 Sensor harness connector to the PCM harness connector.

Fig 1: Measuring Resistance Of O2 Heater Control Circuit

Courtesy of DAIMLERCHRYSLER CORP.

Is the resistance below 5.0 ohms?

Yes >> Replace and program the Powertrain Control Module. See ELECTRONIC CONTROL MODULES article.
See POWERTRAIN VERIFICATION TEST - VER 2 .
No >> Repair the O2 Heater Control circuit for an open.
See POWERTRAIN VERIFICATION TEST - VER 2 .