1996 Ford Van P1351 Code: Ignition Coil or IDM Fault Diagnosis & Fix

P1351 strongly suggests a problem with the Ignition Driver Module (IDM) or an ignition coil. These are the two most likely causes of this specific code. Check for a failing PIP sensor in the distributor or an open resistor in the IDM signal circuit.

I replaced the ignition coil, but the issue persists. I'm now considering checking the IDM module and its associated wiring, especially the 22k ohm resistor in the signal wire to the PCM.

P1351 (IDM Input Circuit Malfunction) and P0300 (Random/Multiple Cylinder Misfire) are critical codes. P1351 is a 'very specific' code pointing directly to ignition system issues — not fuel delivery. You should clear the P1351 first, then monitor if it returns. If it does, that confirms an ongoing issue with the IDM or ignition coil. Before addressing other components like injectors, resolve this specific code. Always prioritize fixing specific trouble codes before general ones.

I've cleared the codes multiple times and they return consistently. The idle is rough — a clear sign of engine misfire. I’ve replaced all spark components, including plugs and wires. I’ll check the 22k ohm resistor in the IDM signal wire as suggested; it’s an often-overlooked component that can cause P1351 if open.

Could a faulty fuel injector be causing the misfire? I’ve tried everything I know, but the issue persists. However, since P1351 is an ignition-related code, it's less likely to be a fuel system problem — especially given that P0300 alone would require extensive diagnostics.

The fact that P1351 returns after clearing the code is a strong indicator of an ongoing hardware issue. This suggests either a failing IDM module or a faulty ignition coil. Since P1351 directly points to ignition problems, it's essential to resolve this before moving on to general misfire causes like injectors. The P0300 code may be secondary — caused by the underlying ignition fault. Always fix specific codes first. Check for open resistors or a failing PIP sensor in the distributor.

Try visiting an authorized Ford dealer. They have access to vehicle-specific technical service bulletins (TSBs), recalls, and specialized tools that may help resolve this issue more efficiently than general repair shops.

Thanks for the helpful input. I’m not ignoring P1351 — I'm just exploring all possible causes while avoiding unnecessary replacements. The advice here has been much better than from the shop that recommended a transmission rebuild. I’ll check the IDM module type and resistor resistance next. I hate sending it to shops only to be told they can’t fix it.

You're welcome! Once you've exhausted all possible DIY fixes, consider taking it to a dealer — they typically have better access to TSBs and recall information. Always start with recalls and then review technical service bulletins (TSBs) for known issues related to your vehicle model and year. Check out this resource: https://www.obd-codes.com/forums/viewtopic.php?t=1913

I found a potential solution — a Ford tech tip indicates that there are two types of IDM modules (gray and black) with different operating characteristics. These cannot be interchanged, and using the wrong module can trigger P1351 after PCM or module replacement. I’ll verify which type was installed in my van to ensure compatibility.