P1663

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

Ignition voltage is supplied directly to the Change Oil lamp The PCM controls the lamp by grounding the control circuit via an internal switch called a driver. The primary function of the driver is to supply the ground for the component being controlled. Each driver has a fault line which is monitored by the PCM. When the PCM is commanding a component ON, the voltage of the control circuit should be low (near 0 volts). When the PCM is commanding the control circuit to a component OFF, the voltage potential of the circuit should be high (near battery voltage). If the fault detection circuit senses a voltage other than what is expected, the fault line status will change causing the DTC to set.

The PCM uses the distance the vehicle has traveled, Engine Coolant Temperature (ECT), engine oil temperature and engine revolutions to calculate oil life. Once a calibrated value is attained, the PCM will ground the lamp control circuit and the Change Oil lamp will illuminate.

The maximum mileage that can be accumulated before the PCM illuminates the Change Oil lamp is 7500 miles. However, the lamp may come ON sooner depending on engine load and temperature (trailer towing, high ambient temperatures, etc.).

CONDITIONS FOR SETTING THE DTC

^ Engine speed greater than 600 RPM.

^ The PCM detects that the commanded state of the driver and the actual state of the control circuit do not match.

^ Condition must be present for a minimum of 5 seconds.

ACTION TAKEN WHEN THE DTC SETS

^ DTC P1663 will be stored in the PCM memory when the diagnostic runs and fails.

^ The Malfunction Indicator Lamp (MIL) will not illuminate.

^ The PCM will record operating conditions at the time the diagnostic fails. This information will be stored in Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC

^ It no failures are reported by this or any other nonemission related diagnostic.

^ A last test tailed (Current DTC) will clear when the diagnostic runs and does not fail.

^ PCM battery voltage is interrupted.

^ Using a Scan tool.

DIAGNOSTIC AIDS

Using Freeze Frame and/or Failure Records data may aid in locating an intermittent condition. If the DTC cannot be duplicated, the information included

in the Freeze Frame and/or Failure Records data can be useful in determining how many miles since the DTC set. The Fail Counter and Pass Counter can also be used to determine how many ignition cycles the diagnostic reported a pass and/or a fail. Operate vehicle within the same freeze frame conditions (RPM, load, vehicle speed, temperature etc.) that were noted. This will isolate when the DTC failed.

TEST DESCRIPTION

Number(s) below refer to step numbers on the diagnostic table.

2. Be sure that both the ON and the OFF states are commanded. Repeat the commands as necessary.

8. If no trouble is found in the control circuit or the connection at the PCM, the PCM may be faulty, however, this is an extremely unlikely failure.