P1357 - IC Output High/Pulse Detected when GND

Introduction:

The diagnostic trouble code (DTC) P1357 indicates a fault related to the Ignition Control (IC) system, specifically when a high or pulse signal is detected from the IC output while the Cylinder 7 ignition coil is grounded. This code often suggests an issue with the Ignition Control Module (ICM), wiring, or the Cylinder 7 ignition coil itself. Understanding the causes and troubleshooting steps is crucial for resolving this problem and restoring proper engine performance.

Table: P1357 - IC Output High/Pulse Detected when GND_Cyl. 7

Topic	Description	Possible Solutions
Code Definition	IC Output High/Pulse Detected when GND_Cyl. 7 - This means the engine control unit (ECU) has detected an unexpected high voltage or pulse signal from the ignition control module (ICM) while the ignition coil for cylinder 7 is grounded. Grounding is a normal part of the ignition process, but the accompanying signal is out of the specified range.	N/A - This is simply the definition of the code. Understanding it is the first step in troubleshooting.
Possible Causes	Faulty Ignition Control Module (ICM), Faulty Ignition Coil (Cylinder 7), Wiring harness issues (shorts, opens, corrosion), Poor grounding of the ICM or ignition coil, ECU malfunction (rare), Interference from other electrical components, Damaged spark plug or spark plug wire (less likely, but possible).	Inspect and test the ICM, Inspect and test the Cylinder 7 ignition coil, Check wiring harness for damage and repair/replace as needed, Clean and tighten grounding points, Rule out other electrical interference, Replace the spark plug or spark plug wire (if noticeably damaged).
Symptoms	Engine misfire (especially on cylinder 7), Rough idling, Reduced engine power, Check engine light (MIL) illuminated, Poor fuel economy, Stalling, Hesitation during acceleration.	Address each symptom individually after identifying the root cause.
Diagnostic Tools	OBD-II scanner, Multimeter, Oscilloscope (for advanced diagnostics), Wiring diagrams for the specific vehicle.	Use the OBD-II scanner to confirm the P1357 code and any other related codes. Use the multimeter to check for voltage, continuity, and resistance. Use the oscilloscope to visually inspect the ignition signal. Refer to wiring diagrams to identify the correct wires to test.
Wiring Inspection	Check wiring harness for: Breaks or cuts in the insulation, Corrosion on connectors, Loose connections, Shorts to ground or other wires, Damaged connectors. Pay particular attention to the wiring running to and from the ICM and the Cylinder 7 ignition coil.	Repair or replace damaged wiring, Clean corroded connectors, Secure loose connections, Use dielectric grease to prevent future corrosion, Ensure proper wire routing to prevent chafing.
ICM Testing	The ICM controls the timing and intensity of the spark. Testing typically involves checking for proper voltage supply, ground, and output signals. Consult the vehicle's service manual for specific testing procedures.	Replace the ICM if it fails any of the tests. Ensure the replacement ICM is compatible with the vehicle. Consider having the ICM tested by a professional if unsure how to perform the tests yourself.
Ignition Coil Testing	Testing the ignition coil involves checking its primary and secondary resistance using a multimeter. An open or shorted coil will have readings outside of the specified range. Also, visually inspect the coil for cracks or other damage.	Replace the ignition coil if it fails the resistance tests or shows signs of physical damage. Ensure the replacement coil is compatible with the vehicle.
Grounding Issues	Poor grounding can cause erratic electrical signals. Check the grounding points for the ICM and the Cylinder 7 ignition coil. Ensure they are clean, tight, and free of corrosion. Use a multimeter to check for continuity between the grounding point and the vehicle's chassis.	Clean corroded grounding points with a wire brush or sandpaper. Tighten loose grounding connections. Add additional grounding straps if necessary.
ECU Considerations	While rare, the ECU can be the cause of the P1357 code. This is usually only suspected after all other possible causes have been ruled out. ECU testing and replacement should be performed by a qualified technician.	Consult a qualified technician for ECU testing and diagnosis. Consider ECU replacement as a last resort.
Related DTCs	P0307 (Cylinder 7 Misfire Detected), P0300 (Random/Multiple Cylinder Misfire Detected), P0357 (Ignition Coil "G" Primary/Secondary Circuit). These codes can provide additional clues to the source of the problem.	Address any related DTCs along with the P1357 code. The root cause may be the same for multiple codes.
Interference	Electrical interference from other components (alternator, sensors, etc.) can sometimes cause false readings. This is rare but should be considered, especially if the problem is intermittent.	Check for loose or damaged wiring to other electrical components. Ensure proper shielding of sensitive circuits. Use an oscilloscope to look for unusual electrical noise.
Oscilloscope Use	An oscilloscope can be used to visually inspect the ignition signal. This can help identify problems such as weak spark, erratic timing, or excessive noise.	Consult the vehicle's service manual or a qualified technician for instructions on using an oscilloscope to diagnose ignition problems.
Service Manual	A vehicle-specific service manual is an invaluable resource for troubleshooting the P1357 code. It provides detailed wiring diagrams, testing procedures, and component locations.	Obtain a service manual for the specific make, model, and year of the vehicle.

Detailed Explanations:

Code Definition: The "IC Output High/Pulse Detected when GND_Cyl. 7" code signifies that the engine's computer (ECU) has registered an unexpected voltage or pulse signal from the Ignition Control Module (ICM) when the ignition coil for cylinder 7 is being grounded as part of its normal operation. This suggests a discrepancy in the normal electrical signal pattern expected during the ignition process for cylinder 7.

Possible Causes: Numerous factors can trigger the P1357 code. These include a failing Ignition Control Module (ICM), a defective Cylinder 7 ignition coil, damaged wiring or connectors in the ignition circuit, poor grounding of the ICM or ignition coil, a rare ECU malfunction, electrical interference from other components, or even a damaged spark plug or wire, although the latter is less common.

Symptoms: The presence of a P1357 code often manifests in noticeable engine performance issues. Common symptoms include engine misfires, particularly on cylinder 7, rough idling, diminished engine power, an illuminated check engine light (MIL), decreased fuel efficiency, stalling, and hesitation during acceleration.

Diagnostic Tools: Effective troubleshooting requires the use of appropriate diagnostic tools. An OBD-II scanner is essential for reading the DTCs. A multimeter is used to measure voltage, continuity, and resistance. An oscilloscope can provide a visual representation of the ignition signal, and wiring diagrams are crucial for tracing the electrical circuits involved.

Wiring Inspection: A thorough inspection of the wiring harness is crucial. Look for any signs of damage, such as breaks, cuts, corrosion, or loose connections. Pay close attention to the wiring running between the ICM and the Cylinder 7 ignition coil. Repair or replace any damaged wires or connectors, and ensure all connections are secure.

ICM Testing: The ICM controls the timing and intensity of the spark. Testing the ICM involves checking for proper voltage supply, ground connections, and output signals. Consult the vehicle's service manual for specific testing procedures. If the ICM fails any of the tests, it should be replaced with a compatible unit.

Ignition Coil Testing: Testing the ignition coil involves checking its primary and secondary resistance using a multimeter. An open or shorted coil will have readings outside of the specified range. Also, visually inspect the coil for cracks or other damage. Replace the ignition coil if it fails the resistance tests or shows signs of physical damage.

Grounding Issues: Proper grounding is essential for the proper operation of the ignition system. Check the grounding points for the ICM and the Cylinder 7 ignition coil. Ensure they are clean, tight, and free of corrosion. Use a multimeter to check for continuity between the grounding point and the vehicle's chassis.

ECU Considerations: Although less frequent, the ECU can be the source of the P1357 code. This is generally suspected only after all other possible causes have been eliminated. ECU testing and replacement should be carried out by a qualified technician.

Related DTCs: The presence of related DTCs, such as P0307 (Cylinder 7 Misfire Detected), P0300 (Random/Multiple Cylinder Misfire Detected), or P0357 (Ignition Coil "G" Primary/Secondary Circuit), can offer further insight into the problem's origin. Addressing these related codes alongside the P1357 code may be necessary.

Interference: Electrical interference can sometimes cause false readings. Check for loose or damaged wiring to other electrical components. Ensure proper shielding of sensitive circuits.

Oscilloscope Use: An oscilloscope can be used to visually inspect the ignition signal, which can help identify problems such as weak spark, erratic timing, or excessive noise.

Service Manual: A vehicle-specific service manual is an invaluable resource for troubleshooting the P1357 code. It provides detailed wiring diagrams, testing procedures, and component locations.

Frequently Asked Questions:

What does the P1357 code mean? It indicates an unexpected high voltage or pulse signal from the ignition control module when cylinder 7's ignition coil is grounded.
What are the common causes of the P1357 code? The most common causes include a faulty ICM, a bad ignition coil for cylinder 7, or wiring issues.
Can I fix the P1357 code myself? If you have experience with automotive repair and diagnostic tools, you may be able to diagnose and fix the problem. However, professional assistance is recommended if you are not comfortable working on your vehicle.
How serious is the P1357 code? The P1357 code can lead to engine misfires and reduced performance, so it should be addressed promptly to prevent further damage.
Will a P1357 code cause my car to fail an emissions test? Yes, the P1357 code indicates a problem that can increase emissions, and it will likely cause your car to fail an emissions test.

Conclusion:

The P1357 code requires a systematic approach to diagnosis and repair. By understanding the possible causes and utilizing the proper diagnostic tools, you can effectively troubleshoot and resolve the underlying issue, restoring your engine's performance and preventing potential damage. Consulting a qualified technician is recommended if you are unsure about any aspect of the troubleshooting process.