Test Step 1 - ACTIVE DIAGNOSTIC TROUBLE CODE (DTC)

WARNING:

When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.

NOTE:

If P0688-AUTO SHUTDOWN RELAY SENSE CIRCUIT LOW has set along with any of the O2 SENSOR HEATER CIRCUIT HIGH DTCs, all of the O2 Sensor Heater Control circuits need to be checked for a short to battery voltage.

Start the engine and allow it to idle for at least 60 seconds.
With the scan tool, read the active DTCs.

Is the DTC Active at this time?

Yes

Go to Test Step 2 - O2 SENSOR 1/1 HEATER ELEMENT

Perform the Checking for an Intermittent DTC diagnostic procedure. Refer to Checking For An Intermittent DTC .