What Does P1351 Mean?
P1351 indicates a malfunction in the Ignition Diagnostic Monitor (IDM) input circuit or an abnormally high voltage on the ignition coil control circuit. The IDM is a feedback signal from the ignition module to the ECU confirming that each spark event occurred. A high voltage condition suggests the feedback circuit is shorted to a voltage source or the ignition module is outputting an incorrect signal level.
Safety Warning
Without proper IDM feedback, the ECU cannot confirm spark events are occurring. This may cause the ECU to shut down fuel injection as a safety measure, leading to engine stalling. The engine may also run rough or fail to start.
Common Causes
30%
Failed ignition control module (ICM) providing incorrect IDM feedback
25%
IDM signal wire shorted to battery voltage or another power circuit
20%
Corroded or damaged connector at the ignition module
15%
ECU input circuit for IDM signal at fault
10%
Aftermarket ignition components with incompatible signal levels
Diagnostic Steps
1
With the engine running, use a scan tool to monitor the IDM signal status. Check if the ECU is receiving any spark confirmation feedback.
2
Measure the voltage on the IDM signal wire at the ECU connector with key on engine off. It should be at or near 0V. If battery voltage is present, trace for a short.
3
Inspect the ignition control module connector for corrosion, heat damage, or melted terminals. ICMs mounted on or near the ignition coil pack are prone to heat-related failures.
4
Disconnect the ignition module and check for proper resistance and continuity on the IDM circuit from the module to the ECU.
5
If using aftermarket ignition components, verify compatibility with the factory ECU IDM requirements. Some performance modules do not provide the correct feedback signal.
Estimated Repair Cost
$100 - $500
Parts + labor, varies by vehicle and location
P1351 indicates a malfunction in the Ignition Diagnostic Monitor (IDM) input circuit or an abnormally high voltage on the ignition coil control circuit. The IDM is a feedback signal from the ignition module to the ECU confirming that each spark event occurred. A high voltage condition suggests the f...
The most common cause of P1351 (IDM Input Circuit Malfunction/ Ignition Coil Control Circuit High Voltage) is: Failed ignition control module (ICM) providing incorrect IDM feedback
Typical repair costs for P1351 range from $100 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Without proper IDM feedback, the ECU cannot confirm spark events are occurring. This may cause the ECU to shut down fuel injection as a safety measure, leading to engine stalling. The engine may also run rough or fail to start.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1351 to identify the root cause.
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Quick Info
Category
Powertrain
System
Ignition System / Engine Control
Difficulty
Type
Manufacturer
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