Ignition

P1351 — Ignition Control Module Circuit Voltage Fault (GM)

Severity: high Do not drive

What P1351 means

P1351 is a GM-specific code for distributor-based ignition systems. The engine computer monitors the ignition control module (ICM) control circuit and its supply voltage. If the voltage or signal falls outside the expected range, the code is stored and spark may be lost or become erratic.

Symptoms

  • No-start
  • Sudden stalling
  • No spark at the plugs
  • Rough running and misfires
  • Check Engine light on
  • Stalling when the engine is hot

Possible causes

  1. Failed ignition control module (ICM)
  2. Open, shorted or high-resistance wiring to the module
  3. Corroded connectors and terminals
  4. Corrosion inside the distributor
  5. Poor module or engine ground
  6. Weak battery or supply voltage problem
  7. Faulty crankshaft or distributor position sensor

How to diagnose

  1. Scan all codes and freeze frame data and look for other ignition-related codes.
  2. Test the battery and charging voltage during cranking.
  3. Inspect the ICM connector and harness for corrosion, damage and heat marks.
  4. Check for spark with a spark tester.
  5. With a multimeter, check power and ground at the module connector with the key on.
  6. Check the reference and module control signals following the wiring diagram for your model.
  7. Remove the distributor cap and look for moisture, corrosion and wear.
  8. Test the ignition module and position sensor, and replace if faulty.

Common fixes

  • Replace the ignition control module
  • Repair the wiring or connector and clean the terminals
  • Restore the engine and module ground
  • Replace a corroded cap, rotor or distributor
  • Replace the battery or fix the supply voltage problem

P1351 on different brands

Chrysler
On Chrysler, this code means the IC (ignition control) circuit voltage is too high.
Dodge · manuals
For Dodge, the listed definition relates to implausible MAF sensor readings, so check the documentation for your exact model.
Ford · manuals
On Ford, the code describes an input fault in the ignition diagnostic monitor circuit.
Hyundai · manuals
On Hyundai, the code points to an open #1 MF signal line.
Land Rover
On Land Rover, it is a malfunction in the ignition diagnostic module circuit.
Mercedes-Benz · manuals
On Mercedes-Benz, the code relates to an injection system sensor or circuit.
MINI
On MINI, the code is tied to cylinder 5 misfire with fuel cut-off.
PSA
On PSA (Peugeot, Citroën) with the Bosch EDC16C34 1.6 HDi ECU, it means the pre-heating relay circuit is incoherent: the relay is supplied but the glow plugs are not.

Questions and answers

What does P1351 mean on a GM vehicle?

It is a supply voltage or circuit fault at the ignition control module on distributor-based systems. The usual culprits are the module, its wiring or corroded contacts.

Can I drive with a P1351 code?

It is best not to. The engine can stall without warning, and misfires can damage the catalytic converter.

Why does P1351 mean different things on other brands?

P1351 is a manufacturer-specific code, so each brand defines it differently. On GM it is the ignition module circuit, but on other makes it can be a completely different system.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.