P1320high severityPowertrain
IC Module 4X Reference Circuit Intermittent No Pulses
on 1996 Chevrolet Astro 4.3L V6 Vortec · RWD
What this code means
The PCM detected intermittent loss of the 4X reference signal from the ignition control module. The 4X reference provides crankshaft position timing information for spark delivery.
Symptoms
- Check Engine Light
- Intermittent misfires
- Engine stalling
- No start (intermittent)
- Rough running
Common causes
- Faulty crankshaft position sensor
- Damaged 4X reference signal wiring
- Ignition control module failure
- Loose distributor (older engines)
- Corroded connector
Diagnostic steps
- Scope 4X reference signal
- Test crankshaft position sensor
- Inspect wiring for damage
- Check IC module connections
- Test distributor pickup (if equipped)
Repair notes
Check crankshaft position sensor and wiring. Replace IC module if signal is intermittent at module.
Other Powertrain codes on this vehicle
P0001
Fuel Volume Regulator Control Circuit/Open
P0002
Fuel Volume Regulator Control Circuit Range/Performance
P0003
Fuel Volume Regulator Control Circuit Low
P0004
Fuel Volume Regulator Control Circuit High
P0010
Intake Camshaft Position Actuator Circuit/Open Bank 1
P0011
Intake Camshaft Position Timing Over-Advanced Bank 1
P0012
Intake Camshaft Position Timing Over-Retarded Bank 1
P0013
Exhaust Camshaft Position Actuator Circuit/Open Bank 1
P0014
Exhaust Camshaft Position Timing Over-Advanced Bank 1
P0015
Exhaust Camshaft Position Timing Over-Retarded Bank 1