What does it mean?
P1371 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: IC Module 4X Reference Circuit Too Few Pulses .
Symptoms
- MIL on with freeze frame data stored
- Extended cranking and an occasional no-start
- Stumble, hesitation or misfire under load
- Tachometer needle dropping or fluttering while driving
- Sudden loss of power, the engine may cut out and restart
Likely causes
- Damaged, rusted or debris covered teeth on the crankshaft reluctor wheel
- Weak or intermittent crankshaft position sensor signal
- Chafed, broken or corroded wiring in the 4X reference circuit between the ignition module and the PCM
- Loose, spread or corroded terminals at the module or PCM connector
- Faulty ignition control module output stage
- Poor module ground or electrical noise from arcing secondary ignition components
- Incorrect sensor to reluctor air gap after a previous repair
How to fix it
- Read the freeze frame and note whether the fault appears while cranking, at idle or under load
- Inspect the 4X reference wiring and both connectors for chafing, corrosion and pushed-back terminals
- Watch engine speed and reference data on a scan tool while wiggling the harness
- Measure supply voltage and ground quality at the ignition module with a multimeter
- Remove the crank sensor and inspect the reluctor teeth for cracks, rust and debris, then verify the air gap
- Scope the reference signal for dropouts before condemning any part
- Replace the crank sensor or the ignition control module, or repair the harness, according to the test results