Inspection Procedure

CODE 12 - G, NE SIGNAL CIRCUIT (NO. 1)

PROCEDURE

1. Check resistance of each pickup coil in distributor.
- Disconnect distributor connector.



- Measure resistance between each terminal shown below.

NOTE: HOT and COLD refer to the temperature of the sensor itself.
COLD: From -10°C (14°F) to 50°C (122°F)
HOT: From 50°C (122°F) to 100°C (212°F)

G sensor (G+ to G-) resistance:
COLD: 185 - 275 ohms.
HOT: 240 - 325 ohms.

NE sensor (NE+ to NE-) resistance:
COLD: 370 - 550 ohms
HOT: 475 - 650 ohms

- If OK proceed to step 2.
- If not OK replace distributor housing assembly.

2. Check for open and short in harness and connector between ECM and distributor.
- If OK proceed to step 3.
- If not OK repair or replace harness or connector.

3. Check air gap.
- Remove distributor cap and rotor.



- Using a non-magnetic thickness gauge measure the air gap between the signal rotor and sensor projection.

Air gap: 0.2 - 0.4 mm (0.008 - 0.016 in).

- If OK check and replace ECM.
- If not OK replace distributor housing assembly.

INSPECTION USING OSCILLOSCOPE



- During cranking or idling, check waveforms between terminals G+ and G-; NE+ and NE- of ECM.
- The correct waveforms appear as shown in the illustration.