P0243 diagnosis points to bad ECU.

[MX5racer]

CEL prompted a scan of the computer and the code was p0243 " Turbo waste gate". Did diagnosis per Dodge Shop Manual and have concluded it to be the Waste Gate driver circuit #1 pin out on the C1 ECU connector. This is the first bad ECU that I have ever experienced, on any vehicle. Is this common in these trucks? My truck is all stock w/ 200,000 miles. I am the original owner.

 

[p-Bar]

MX5 I think I had that code quite a few years ago . I had a blown fuse I think #36 and some said to look at the wire that is going under the air cond.compressor that it shorts the the 5 volt signal to the wastegate. It was common enough to be brought up here. I'll see if I can find the thread. Check these out. I like the idea of the 150 ohm resistor which you can do at the wastegate and see if you can reset the code if not then you need to trace the wires up to the ECU.
https://www.turbodieselregister.com...t&forumchoice[]=127&childforums=1&exactname=1

 

[MX5racer]

Went through the blown fuse scenario a few years back, power side of this circuit is also the power side of the fan clutch. my fan clutch was bad thus blowing the (actually) #6 fuse thus the p0234 code at that time. I replaced the fan clutch and all was good until last week when I got a CEL. Went through the factory diagnostic procedure and I have no short to ground, no short to another circuit, I have 12 volts to the solenoid, solenoid is not open or shorted, all wiring in tact, continuity in the circuit but it gives up at/in the ECU. By the way my truck is a 2006.

 

[p-Bar]

Did you buy a factory fan clutch? guys are reporting bad results with the aftermarket units.

 

[MX5racer]

Power side of the circuit is not the issue. All checks. Issue is the 12v is not being switched to ground by the ECU. Circuit starts at the Ing+ hot through the harness to the solenoid and back to the ecm which controls the sol. by switching the circuit to ground. I have 12 v all the way through the circuit but the ECM is not switching to ground.

 

[p-Bar]

Well I think you answered your own question.

 

[MX5racer]

The question was... Is ECU failure in these trucks common? Not... What caused the P0234 CEL.

 

[p-Bar]

Did you buy a factory fan clutch? guys are reporting bad results with the aftermarket units.

 

[p-Bar]

Don't hear of many failures but they do happen even mil-spec circuits fail. Some of the guys have used "goecm" and have had good luck with reworking their old ecm.

 

[MX5racer]

Thanks p-Bar. I will check with goecm.

 

[TRAMPLINEMAN]

Check the wiring going to the actuator. The wires in the pigtail break and throw the 0243 code. It's a common problem. They break/crack right next to the actuator.

 

[sag2]

Bad ECM is highly unlikely. Poor connection is more likely. Cut the control wire and ground it and see if the code changes to another code.

 

[MX5racer]

Which of the two wires are you calling the "control" wire. My harness has a +12v switched lead and an ECM trigger lead (Ground). Grounding the +12v will blow the #6 fuse and grounding the ECM trigger lead will either activate the solenoid or ground the trigger lead(ground to ground)depending which end of that lead I ground. Have you studied this particular circuit schematic?

 

[Wayne M.]

Do you have access to an advanced scan tool like a solus or Autoenginuity ? I've never had to look at that particular PID, but it would help to "see" what's going on.

 

[PWong]

Which of the two wires are you calling the "control" wire. My harness has a +12v switched lead and an ECM trigger lead (Ground). Grounding the +12v will blow the #6 fuse and grounding the ECM trigger lead will either activate the solenoid or ground the trigger lead(ground to ground)depending which end of that lead I ground. Have you studied this particular circuit schematic?

There are 8 steps of diagnostics.
Step 1 - 7 will conclude the integrity of circuit F504, K139 and the wastegate solenoid. In step 8, if the ECM failed to perform a self check of the circuit after 30 seconds then replace the ECM.

Step 8 is the same as step 2.
The fuse should be #36.
Are you sure the connection at ECM C1 pin1 is good?

 

[MGreer]

Did you try an ohm test through the wastegate solenoid. Instructions from the Holset website say the ohm's should not be below 6 ohm's, if they are replace the solenoid. My truck wouldn't build over 22 psi of boost, the ohm's tested at 1.4. I bought another solenoid and it tested at 10.5 ohms. Installed new solenoid and everything back to normal. I didn't receive any codes when this happened.

 

[sag2]

There are 8 steps of diagnostics.
Step 1 - 7 will conclude the integrity of circuit F504, K139 and the wastegate solenoid. In step 8, if the ECM failed to perform a self check of the circuit after 30 seconds then replace the ECM.

Step 8 is the same as step 2.
The fuse should be #36.
Are you sure the connection at ECM C1 pin1 is good?

Keep in mind if you are using the OEM diagnostic procedure and the fault is stored any testing will always lead to the module. If the code is active and stays active after clearing the procedure should be followed.
That is the reason so many modules get replaced. The procedure says in step one is fault active? Yes, go to 2, no stop as the fault is intermittent.

 

[MX5racer]

I did all 8 steps twice, steps 2 & 8 (4) times (per factory shop manual)and some additional diagnosis with a DVOM and 12v test light. Also took the C1 connector out and did a visual and electrical continuity test(s). I have been unable to find a defect in the harness or connectors. Fuse in my truck is #6 not #36. I will check again after I clear the fault. Thanks Sag2.

 

[cerberusiam]

Also took the C1 connector out and did a visual and electrical continuity test(s). I have been unable to find a defect in the harness or connectors.

If you have continuity on the harness and the resistance is not high, it is one of 2 things: the ECU is bad and that circuit has failed internally, or, the connector is not contacting on that pin. The ECU based control systems and EXTREMLY picky about amperage on the circuit, a short will burn out the circuit in the ECU. If you replace the ECU back check all of the harness where the 12V feed is to make sure you do not have a partial short on the system. It is also quite possible the connector female end has spread enough it will not make contact anymore, especially on the older trucks that is a typical problem. In that case you can get a patch wire from Cummins to replace the connector end of it.

 

[MJWenrich]

This may not apply to your truck but I received a letter from Chrysler that the ECM warranty on my 2004.5 has been extended to lifetime coverage. The letter states that it only applies to 2004/2005 2500/3500 5.9 engines that are equipped with California emissions. It relates to state mandated inspections and not complete failure but the letter was dated 2010 and maybe failure is now an issue as well. If you have a very early 2006, maybe it has a 2005 ECM. Just for your information in case you find a connection to this issue and your problem.