P1663

DTC P1663 Generator Lamp Control

Circuit

Charging:

Circuit Description

The PCM turns ON the bulb, LED, or driver info center indicator by supplying a path to ground through the PCM.

Conditions for Setting the DTC

- Ignition is ON.
- An imprper voltage level has been detected on the cruise inhbit output driver circuit.
- Above conditions for at least 20 seconds.

Action Taken When the DTC Sets

- The PCM will not illuminate the Malfunction Indicator Lamp (MIL).
- The PCM will store conditions which were present when the DTC set as Fail Records data only. This information will not be stored as Freeze Frame data.

Conditions for Clearing the MIL/DTC

- A history DTC will clear after 40 consecutive warm-up cycles have occured without a malfunction.
- DTC can be cleared by using the scan tool. Clear Info function or by disconnecting the PCM battery feed.

Diagnostic Aids

A PCM controlled lamp ON at all times most likely indicates that a condition is present which required the attention of the vehicle operator. Conditions which will illuminate each lamp are as follows:

- When the engine speed is greater than 1200 RPM and system voltage falls below 10 volts for longer than 10 seconds. The PCM commands the generator ON when system boltage rises to above 12 volts.
- When the generator control circuit (L terminal) remains low for longer than 10 seconds.
- When the engine speed is below 2000 RPM and the generator PWM control circuit (F terminal) duty cycle remains low for longer than 20 seconds.
- When the engine speed is above 4000 RPM and the generator PWM control circuit (F terminal) duty cycle remains high for longer than 20 seconds.

For diagnosis of the instrument panel, perform the System Check Initial Inspection and Diagnostic Overview.

- Poor connection at PCM. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperlu formed or damaged terminals, and poor terminal to wire connection.
- Damaged harness. Inspect the wiring harness for damage. If the harness appears to be OK, disconnect the PCM and turn the ignition ON. Observe a voltmeter connected to the affected PCM output cicurit while moving connectors and wiring harnesses related to the PCM output circuit. A change in voltage will indicate the location of the fault.
- Engine Oil Level Sensor circuit: If the problem was with the Low Oil Level lamp and Chart C-16A did not isolate a problem, use Chart C-16B, Engine Oil Level Sensor Diagnosis.

Test Desciption

Number(s) below refer to the step number(s) on the Diagnostic Chart.

3. Normally, ignition feed voltage should be present on the output driver circuit with the PCM disconnected and the ignition turned ON.
4. Checks for a shorted component or a short to B+ on the output driver circuit. Either condition would result in a measured currect of over 1.5 amps. Also checks for a component that is going open while being operated, resulting in a measured current of 0 amos.
5. Check for a faulty instrument cluster.
16. This vehicle is equipped witth a PCM which utilizes an Electrically Errasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed. Refer to PCM Engine Control Module.