P0606 when passing 3500rpm and fail safe.

[dani9678]

I'm working on a 2004 Mountaineer that has the 4.0sohc v6. When you pass 3500 rpms the engine goes into fail safe. I connected my analyzer to it and monitored the wheel sensors because I read that one of them when faulty could cause the engine to go into fail safe. They are all working fine. If I rev the engine until it hits 3500 it will also go into fail safe so it doesn't have to be moving. I also get another code P2106 stating that the TAC forced limit reached. But it doesn't store immediately like the P0606 code.

 

[dani9678]

The engine also runs rough at idle but straightens out while driving. I replaced the plugs, wires, fan clutch, and also the crank and cam sensors because I kept getting codes for them. The only code I get now is the P0606 if I go over 3500 RPM. I read that there is an ECM update to correct the rough idle and some other issues. Do you think this would correct the failsafe P0606 code also?

 

[2000StreetRod]

ECM Internal Communication Error

P0606 Ford - ECM Internal Communication Error

P0606 Ford Description

The Engine Control Module (ECM) continuously monitors its internal memory status, internal circuits, and output signals to the throttle actuator. This self−check insures that the ECM is functioning properly. If any malfunction is detected, the ECM will set the code and illuminate the engine light.

The electronic throttle control is a closed system (control and feedback). I suspect the PCM is not reading the commanded throttle position. See the following: 2005 Ford Explorer with SERIOUS problems, Ford Garage hasn't even been able to fix

Also, check the harmonic balancer: Harmonic balancer failure
The balancer may have moved laterally and damaged the crankshaft position sensor.

 

[dani9678]

So do you think the issue is with the throttle position sensor? I didn't see any problems with the crank pulley. I read the links. The second link I had already seen before. Unfortunately they never finished the thread.

 

[2000StreetRod]

electronic throttle control

I think the PCM is more reliable than the electronic throttle control. Since an unreliable throttle control is unsafe the PCM monitors the reported position and compares that to the commanded position. I suspect when the two differ the PCM reverts to rev limiting and declares a fault. However, it can't determine the actual source of the fault. I'm not familiar with electronic throttle control and prefer the 2003 and earlier mechanical control. It may be possible to clean the throttle plate. You might try using two people to monitor its operation with the ignition on but the engine not running. There is probably a significant mechanical advantage (gearing) between the electric motor and the plate. Don't try to manually force the plate open and closed since that will probably damage the device.

 

[dani9678]

If the ECM ends up faulty and I got one from an Explorer with the same engine and transmission and also grabbed the ignition key to go with it for PATS, would I be able to start the Mountaineer without having to have the ignition system reprogrammed for the key since the key was with the Explorer that the ECM came out of?

 

[2000StreetRod]

how to determine

How do you plan to determine if the PCM is faulty? I wouldn't trust the DTCs generated by a faulty PCM. If you take it to the dealer for testing I suspect they'd reprogram it as part of testing.

I wouldn't worry about getting another PCM until you check out the throttle control. If you try to use the PCM and ignition key from another vehicle you may have to get the PATS receiver also. I think at some point on the later year vehicles the VIN is associated with many of the electronic modules.

 

[dani9678]

Well, now it won't even turn over with the key. I pulled a code for B1213. He only has one key.