PCM Health Check?

[JWA]

Got an 05 E-350 gasser and have noticed a few minor glitches that might be related to the PCM. One is intermittent VSC operation that does NOT seem to be related to any of the controls---its works fine some days, others it won't engage. Interesting enough when it's "failed" if I shut down, wait a few seconds and restart I'll have VSC then.

Naturally I first suspected the steering wheel controls, bought a new Ford set but have not yet replaced them since discovering the above-mentioned "fix".

Also on occasion the CEL comes on, DTC shows an issue with the throttle body that also corrects with ignition off and back on.

A comment by CarringB concerning the '05 might have first-year issues with the PCM I'm somewhat considering buying and installing a brand new Ford PCM.

So I'm wondering if there's a check of the PCM as a deciding factor whether to replace it pre-emptively? Those who've replaced a PCM what steps are necessary to complete the installation after its physically in place and all wiring harnesses connected?

TIA!

[motovan_mn]

I don't know about a health check, but I've owned two older fords (1992 F150 and a 1995 E250) that both had PCMs go bad overnight. One day the vehicle drives fine, the next day the vehicle cranks but won't start because the fuel pump isn't turning on any more. Something about the old capacitors in the PCM's leaking/failing due to old age.

Replacing the PCM was as simple as ordering up a refurbished unit and plugging in. No programming or anything required. Not sure if anything has changed for the newer models. I ordered once from autoecms.com and once from rockauto.com. Both worked fine.

[arctictraveller]

I wonder if the factory manuals for your year would have a troubleshooting section for the PCM? My 2001 manuals have lots of point to point testing steps for many of the circuits.

[carringb]

I don't think you'd be affected by one of the defective PCMs this late in the game. Your PCM is susceptible to damage during welding operations (https://madocumentupload.marketingas...8e21e&v5=False) but I don't think that would cause your symptoms. I'd put my money on a failing position sensor in the throttle body, or possibly a bad ground strap between the intake and windshield cowling, or maybe the one mentioned in Step-3 in the PDF above.

Does your code reader display "pending" codes? It would be interesting to see of any pending throttle-body codes correspond with the no-VSC condition.

[motovan_mn]

Originally Posted by carringb

I don't think you'd be affected by one of the defective PCMs this late in the game. Your PCM is susceptible to damage during welding operations (https://madocumentupload.marketingas...8e21e&v5=False) but I don't think that would cause your symptoms. I'd put my money on a failing position sensor in the throttle body, or possibly a bad ground strap between the intake and windshield cowling, or maybe the one mentioned in Step-3 in the PDF above.

Does your code reader display "pending" codes? It would be interesting to see of any pending throttle-body codes correspond with the no-VSC condition.

That's a good service bulletin to keep in mind. I wonder if the major 4x4 conversion players (UJOR, Quigley, Quadvan, etc...) follow all those steps prior to welding anything. I hate to be "that guy" but maybe I'll double check with UJOR before they start hacking away

[JWA]

Originally Posted by carringb

I don't think you'd be affected by one of the defective PCMs this late in the game. Your PCM is susceptible to damage during welding operations (https://madocumentupload.marketingas...8e21e&v5=False) but I don't think that would cause your symptoms. I'd put my money on a failing position sensor in the throttle body, or possibly a bad ground strap between the intake and windshield cowling, or maybe the one mentioned in Step-3 in the PDF above.

Does your code reader display "pending" codes? It would be interesting to see of any pending throttle-body codes correspond with the no-VSC condition.

My Actron code reader does indeed read pending codes however the so-far only time I've had a "forced idle" code it was an immediate occurrence, corrected after shutting down and restarting. The next time I suspect something similar was a relatively cold day, engine struggled to stay running, the SES dash lamp illuminated. Shutting down and restarting cured that, did not think to query the PCM for any code.

Regarding the TSB my van does have the raised roof with steel tubing "roll cage" welded to the body but that seems to not be an issue.

I will double check the mentioned ground wire---the engine has been in and out a few times so that very well could be an issue.

Thanks for all for contributing. My thought was some time ago CarringB mentioned the '05's had possible PCM issues given the first year of the CAN-bus addition. I must have missed or not understood that was related to welding operations too close to it's physical location.

Should the forced idle event happen again I'll be sure to probe for pending or confirmed DTC's.

[carringb]

Forced-idle can also happen if any of the TPS/can-bus signals are momentarily interrupted. So it’s a good idea to check all the engine wire harness connectors. Those big ones with the retainer bolts. I’ve seen plenty where somebody forgot to tighten the bolt down. Same with the one that secure the wire main to the PCM.

[Vanzila]

Originally Posted by JWA

Got an 05 E-350 gasser and have noticed a few minor glitches that might be related to the PCM. One is intermittent VSC operation that does NOT seem to be related to any of the controls---its works fine some days, others it won't engage. Interesting enough when it's "failed" if I shut down, wait a few seconds and restart I'll have VSC then.

Naturally I first suspected the steering wheel controls, bought a new Ford set but have not yet replaced them since discovering the above-mentioned "fix".

Also on occasion the CEL comes on, DTC shows an issue with the throttle body that also corrects with ignition off and back on.

A comment by CarringB concerning the '05 might have first-year issues with the PCM I'm somewhat considering buying and installing a brand new Ford PCM.

So I'm wondering if there's a check of the PCM as a deciding factor whether to replace it pre-emptively? Those who've replaced a PCM what steps are necessary to complete the installation after its physically in place and all wiring harnesses connected?

TIA!

Like the rest have said this is likly Not your PCM. More than likely vacuum leak our bad IAT or TB components.. Remember your PCM does not get in to Closed loop until its at operating temp. So if its not getting to closed loop it will act as you have described. You can have a Stuck open Thermostat that will cause all of these Cels ..If you dont get into Closed loop then the PCM will throw lots of Errors like bad o2 sensors etc.. But its all because your not at temp. Have you done a Vacuum Check ? You also have a Vacuum control on your Fuel Rail... If that is bad then you can have a small vacuum leak that would allow to much fuel Pump Pressure on the Rail.

I just had to fix this on my 5.8l.

[JWA]

Been a few days and thanks so much for the input so far--very much appreciated!

As things have wound on twice I've experienced the "forced idle" situation (DTC's P2104 & P2112) According to my Actron scanner's "code connect" feature where they list possible fixes or often-posted causes of a DTC; both point to possible wiring issues between the electronic throttle body and throttle position sensor (gas pedal )

I will mention the latest three times this has happened we've had very cold and unusual temperatures locally. Every time this has occurred it self-corrects by shutting down and nearly immediately re-starting. This has never happened during our "normal" temperatures.

I suspect my issues are in the wiring so that's on the list of things to check. I've never fiddled with the throttle position sensor connector but did remove the actual throttle body some time ago. Sadly I don't recall how long between these events, again its not a common problem.

I have a friend with advanced-level Ford diagnostic skills I'll ask to check the TPS for its proper operation. I'll also triple check the TB connector for being tightly connected, same with the TPS inside the cabin.