Test Notes and Schematics

CHARGING SYSTEM VOLTAGE





Electrical Schematic-Diagnostic Trouble Code 22


Normal Operation
The diagnostic monitor measures voltage at Pins 11 (Circuit 614, GY/O) and 12 (Circuit 623, P/W). The voltage at these pins is controlled by two resistors inside the diagnostic monitor and the voltage varies with charging system voltage (the expected voltages at Pins 11 and 12 are shown in the charging system voltage chart above. If the voltage at both of these pins exceeds 5 volts, the diagnostic monitor will flash out code 22.

Possible Causes
High voltage at Pins 11 and 12 can be caused by:
1. A short in the wiring harness between Circuits 614 (GY/O) or 623 (P/W) and another wire can cause high voltage on these circuits.

NOTE: The wiring harness leading to the safing sensor carries higher voltage circuits that may short to Circuits 614 and 623.

2. A short in the clockspring between Circuit 614 or 615 and some of the horn or speed control wiring.
3. A short across the normally open contacts of the safing sensor.

NOTE: The voltage on Circuits 611 and 612 inside the safing is usually battery voltage or higher. There should be an open circuit across the contacts of the safing sensor if the sensor is operating normally. If the sensor contacts are closed, the voltage on Circuits 614 and 623 would be high (at least battery voltage).

4. Vehicle charging system voltage too high. if the generator output voltage is too high (greater than 17 volts) it may cause a code 22 to occur.