02 F150 4.2L 4WD – Wont start mostly in high humidity. Theft light flashing continuously.

ID Status Date Year Make Model Transmission Type A/C Controls Public/Private
#16141 Closed 2002 Ford F-150 4.2L V-6 public

This problem is similar to your post from 03/2016. The difference is that it mostly (not always) acts up when humidity is high. I checked the power relay and it is fine (battery volts at MAF with key on). According to the post I observed to theft light. It flashed rapidly for 2-3 minutes continuously without indicating any codes. Usually, when the atmosphere dries out, it will start like never a problem.
I think it is a poor power connection at the PCM, but am lost to figure out where.


The 2003 F150 that I wrote the article about was also distinguished by the odometer displaying all dashes instead of digits symptom and theft codes stored. Does your truck also have these conditions?

I would recommend beginning the diagnosis with having the codes read in all of the vehicle computers/modules. I would record the codes and modules, clear the codes and then recheck after the symptoms present again.

If having the codes checked is not a possibility then you would need to go with some more basic test/observations.

Spark, fuel pressure, injector pulse, check engine light working.

This morning before work the truck still would not start – it didn’t all weekend. So I checked for codes:
PCM – no codes
ABS – no access/comms
TCM – no access/comms
OBD2 – no access/comms
Also the odometer was blank. No dashes or numbers. May also be due to the broken solder joints.
MIL seems to be working ok. Did not have time to check other listed functions.
When I returned home, the truck started like normal.


Okay, Just keep in touch through this question when it acts back up.  Sparky


Not sure if the system will allow a video sized file or not but you can try send it as an attachment. If not, upload it to YouTube or something like it and send me the link.

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