What Does P1358 Mean?
The Ignition Diagnostic Monitor (IDM) signal to the PCM is reading outside expected parameters during self-test mode. This indicates a calibration or communication issue between the ignition control modules.
Common Causes
35%
Faulty Ignition Diagnostic Module (IDM)
30%
Intermittent wiring connection between IDM and PCM
15%
Low battery voltage during self-test affecting signal quality
12%
PCM internal fault in IDM signal processing circuit
8%
Poor ground connection causing signal distortion
Diagnostic Steps
1
Step 1: Verify battery voltage is above 12.4V and charging system output is 13.5-14.5V
2
Step 2: Perform key-on engine-off self-test and monitor IDM signal voltage with scan tool
3
Step 3: Wiggle-test all wiring and connectors between IDM and PCM while monitoring signal
4
Step 4: Check signal wire for proper resistance and freedom from shorts or opens
5
Step 5: Compare IDM signal waveform to manufacturer specifications using oscilloscope
Estimated Repair Cost
$150 - $750
Parts + labor, varies by vehicle and location
The Ignition Diagnostic Monitor (IDM) signal to the PCM is reading outside expected parameters during self-test mode. This indicates a calibration or communication issue between the ignition control modules.
The most common cause of P1358 (Ignition Diagnostic Monitor Signal out of Self-Test Range) is: Faulty Ignition Diagnostic Module (IDM)
Typical repair costs for P1358 range from $150 to $750, depending on the vehicle, location, and whether you do it yourself or go to a shop.
May cause intermittent driveability issues including hesitation or stalling. Vehicle may fail emissions testing.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1358 to identify the root cause.
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Quick Info
Category
Powertrain
System
Ignition System
Difficulty
Type
Manufacturer
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