2005 Mustang - Dealer says PCM Driver needs to be replaced!


New Member
Feb 13, 2019
bakersfield, ca
Hi everyone,

I am currently having issues with my Mustang 2005 ENG:4.0_Liter, I hear a knocking noise under the hood every time I am at a stop light pressing the brake and yesterday it suddenly stalled and had to shift back to parking and turn it back on again, and not the first time that this happens.

I changed the EGR valve and cleaned the throttle body thinking these were the problems, but the same engine shaking continued. I've been having these issues for more than two months now, and can't figure out what it is.

Finally, I took it to the dealer today to get a diagnostic and they said the PCM Driver needed to be replaced; the thing is that they want to charge me quite a lot in my belief.

Labor - $455
Part - $951
Key - $30 (I declined, told them I had an extra)
Freight - $133 (They said to get the part as soon as possible)

The codes they found were P0401, P0059, and P0053 and the paper said DIAG FOUND BAD PCM DRIVER, NEEDS REPLACED PCM.

Anyway, I was wondering if anybody could suggest anything to get this for cheaper then what they are charging me for. For example, I think this is the part I think needs replacement and seems to be much less expensive then what they want to charge me for it:


Any help or suggestions will be highly appreciated!


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Active Member
Jul 12, 2018
Hi, Sorry to hear. Dealer Price sounds close for that repair. So, Codes suggest impeded or insufficient EGR flow, and upstream Heated Oxygen Sensor(s) (HO2S) Resistance is out of range at both Bank 1,Sensor 1 & Bank 2, Sensor 1.
I’d peeked at the the printout. If they’ve run diagnostics and found this, it meant an anomaly in communication & generally correct. I’d otherwise attempt to disprove the theory, ask if any recent Exhaust mod’s or X Pipe, long tube headers, is it running a Stock Tune, Check 02’s Wiring, watch them live while running on a Scantool, other troubleshooting, load connectors with Dielectric grease, etc.
The Car runs on its default Maps (open loop) until it’s warm, then factors in/runs off of sensory input. Do you have these issues when the Car is not warmed up?
Stalling, erratic Mileage, performance symptoms line up with 02 sensor issues.. ECM’s can do some unusual things when malfunctioning, (the low RPM knocking I’m questioning if related, oil pressure OK?), but the Codes you’re showing don’t seem all that erratic. I’ve seen CPU’s components requiring replacement with melted wires 02 wires on Headers, have also seen them clear up just fine once the anomaly is corrected.
Ford likely pinned out the unplugged Wiring to the 02’s to verify no shorts are occurring, or an issue. You may want to check fuse F45 (10A) in the BEC, the associated 02H fuse for your Genre’.
Heres the rub. Another thought. If you shell out the Grand & they DO replace your Computer, if that’s NOT the issue, you need to be certain you’re not going to “eat” it. I’d suggest verifying that with them. Maybe call around to other local’s and get prices. There’s always room for negotiation, especially if you have been there previously, or, if you show interest in coming back, I.e. I love that Car in the lot, May I have a Carfax”, etc..
Since the 90’s, I have setup, repaired, rechipped and modified CPU’s of most makes & models, mostly OBD-0, OBD-1, and since 2005: OBD-2’s. Note, some were sent here for repair, but were absolutely fine. There are some seedy Companies online..
Questions to ask Mail order repair facilities:
As for sending it off to a repair facility, with the right tools its not rocket science to repair them, they may just reprogram an already repaired CPU. Tell them you want yours repaired, not another. Verify they have the latest Ford Software platform when reprogramming & how they support PATS system synchronization (generally reprogrammed once you reinstall a different ECU in the Car). You may have to do a TPMS relearn, that’s simple & not costly, do it yourself.
The PATS transceiver is mounted on the ignition lock cylinder housing and is connected to the PATS control module. The key’s electronics do a handshake with it, and is integrated into the Computer. With a physically different ECU, You may need the Dealership afterwards to program the key, that & FOB pairing ALONE is around 250$. With a new ECU, the Car may not start without- or may just flash the Security light. Yes, you can override it- with the right tools, or a relearn- but it sounds like you simply want your Car repaired correctly, reasonably.
There’s also the replacement of all COP’s that may be required (a warranty necessity) as well as courtesy light time programming, and- depending on how bad an ECU was, sending them exact mileage & reverifying your VIN#. Give them a call & find out how they respond to those questions. Then weigh that with the Cost of it done, correctly- guaranteed by Ford..& they eat the Cost, if wrong. But the Car has everything done, it fails- Ford’s problem. If you go with them, I’d wait on the expedited shipping, if possible- that’s IS ridiculous!
Hope that helps, good luck!


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