SureTrack Real Fix: It’s Not a Misfire!

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Real Fixes from Mitchell 1’s SureTrack® expert information resource are documented issues from actual shop repair orders and community discussions. Read on to see how SureTrack can help you correct issues that are not easily diagnosed using OEM information alone. SureTrack is available at no additional cost in our ProDemand product.

When a vehicle has a misfire symptom, you start with the basics and go from there. If you check and recheck everything, you as the experts for help. SureTrack community member bmaples had a Ford Explorer in their shop that would stumble or cutout above 45mph but they checked everything and that wasn’t it. They posed the question to the community, and with the help of fellow community member Ericsautomotive and others, they were able to resolve the issue quickly.

The following Community Fix summarizes the interaction between members of the community that led to the solution.

Vehicle
2015 Ford Explorer XLT 3.5L

Title
Misfire symptoms above 45mph, rebuild transmission.

Complaint
Customer complains that vehicle stumbles or cuts out when driving above 45 miles per hour.

Diagnostic Steps Performed/Parts Replaced
Took vehicle on test drive and when traveling around 45mph and up, and stable cruise, and with light accelerator pedal application the vehicle stumbles/cuts out like a misfire. Scan revealed P0430 for B2 Cat efficiency stored as pending in the PCM/TCM but testing of it revealed no concern. The exhaust temperature increases 250 to 300 degrees between the upstream and downstream. Downstream O2 sensors are fixed around 600 MV. I did a complete scan and found the following codes ABS: U3003-16 for battery circuit voltage below threshold and U0401-68 for invalid data received from ECM/PCM A – Even Information – Not Current DTC. Anti-Theft (PATS) B1310-14 Run/Start Control – Circuit short To Ground Or Open – Not Current DTC and P0230-14 Fuel Pump Primary Circuit – Circuit Short To Ground Or Open – Not Current DTC. Those last two codes are also stored as Not Current in the TPMS/Body Control modules. I’ve driven while watching the live data to see if any PIDs drop out. Next step is to clear the codes and see if they store again while the symptom occurs. I will see if those modules share a power or ground that could be dropping out.

Has anyone seen this before and know where I should start as far as connecting my DVOM and test lamps to find the culprit? Any tips or guidance is greatly appreciated.

Best Answer from Community Member Ericsautomotive
Check Mode6 for possible misfiring? That alone will drive the fuel trims crazy and give you this symptom (cat codes). Remember, it takes Ford products forever to set misfire codes unless you unplug a coil or injector.

Cause
Double and triple checked everything that could cause a misfire and the other codes and could not find the cause there. Expanding to other systems, found that transmission was the cause of the stumbling.

Correction
Transmission rebuild corrected the issue. Vehicle no longer stumbles or cuts out while diving.

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About the Author

Nick Taylor

Nick Taylor is the SureTrack Community Administrator and a Senior Applications Specialist at Mitchell 1 with over 25 years of experience with electronic repair data systems. Nick previously worked in the automotive dismantling and engine rebuilding industries.