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Discussion Starter #1
Sorry for the long painful story of my 2005 Range Rover.

Blew coolant hose on back of engine on freeway after quick acceleration passing someone. Luckily I was close to home, coolant and smoke everywhere. It never overheated, drove it in garage and ran fine. Replaced plastic fitting and hose and when I went to start it to bleed the coolant the engine failsafe mode came up. Quick scan indicated throttle actuator spring test failure. Read up on that and disconnected the MAF and then failsafe mode went away and it ran and drove fine. Based on many articles I thought the problem was my throttle body, luckily my BMW X5 has the exact same throttle body so I swapped the two. Error was still on my RR and my BMW drove perfectly the the RR throttle body. Hooked up a SnapOn modis scanner and read all the throttle position sensors and settings and at some point in testing wiring I lost all readings. Seemed like the ECU was messed up so I bought a used one, with a key and immobilizer. After installation I get all the correct readings with throttle at rest and wide open (see photos). The only issue I have is the ECU thinks the throttle is 100% open (see photo). It is currently in the Engine Failsafe mode with the throttle actuator control error, I would think if the ECU thinks the throttle is wide open it would be in failsafe mode. Based on all my reading it appears as though when you replace the ECU you need to reset the adaptation of the throttle to the ECU. Wondering if anyone can confirm if that could be the reason the throttle shows 100% open. I did try to disconnect the battery, wait 10min then rub the two cables together to reset ECU and that did not work. Also emailed Comms software and their software will not do throttle adaptation. I did find all the wires and test continuity from the throttle body pigtail to the ECU and they all checked out. Would appreciate any thoughts.

IMG_1259.jpg IMG_1260.jpg
 

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Discussion Starter #3
Thanks, I will try that. Did you try to start it before you did this process? And if so can you tell me what it was doing? When I swapped the two I didn't have to do anything with my BMW and it just worked.
 

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I did the reset procedure before trying to start the car. the package on the new throttle body said programming is required. so that is why I did this first. My RR failed the exact way you're did, failed test. My Indy had scanned it to diagnose it and probably erased the faults as well. So that could also possibly be your problem
 

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Discussion Starter #5
I tried the reset process and it didn't work. I have also cleared all the codes but the Throttle Actuator Control Error never goes away.

When you say yours failed in the same way can you describe your pain and suffering a little more?
 

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When mine failed, I got the engine prog failsafe error message on the dashboard. The car ended up dying on me. I had to unplug the MAF in order to get the car home. So I took it to my local Indy for diagnosis and they confirmed the throttle body was bad. They said it failed a self test. They said that the reason I was able to make it home via unplugging the MAF was because it goes into a default program. What symptoms are you having?
 

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Mine was triggered by a heater hose blowing out.
That seems like a weird reason for the throttle body to go out. I just replaced all 11 or so hoses and I don't see how that would be related.

I just noticed the 11.8 v on your battery. That seems low.
 

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Discussion Starter #9
Heater hose while blowing out going down the freeway. I have a new battery but it has been sitting for a couple weeks when I took these photos. I will try to charge, test the battery, then see if the ECU updates the voltage.
 

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Recheck your wiring.

I would bet that you are shorted to another wire in the harness, TV1 should not be that high ever, it is ~0.5-2V, TV2 goes up to ~4.5V, both are higher voltage at WOT.
 

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Discussion Starter #11
I checked continuity between the throttle body to the ECU plugs while they were disconnected and those checked out. For the record the front of the engine and ECU were fairly dry, it was the back of the engine that got the antifreeze bath. Is it possible its the harness to the pedal?

Recheck your wiring.

I would bet that you are shorted to another wire in the harness, TV1 should not be that high ever, it is ~0.5-2V, TV2 goes up to ~4.5V, both are higher voltage at WOT.
 

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Harness to the APP sensor(pedal) will throw different faults, and your pedal data is reading correctly in the screenshot.

Just having continuity from one of of the wire to the other end, does not mean that that wire isn't shorted out to something else. I would start by ohming out each TB pin to each other TB pin with the TB and ECM disconnected, but it could easily be another wire in the harness.

Were there any other fault codes stored, P1615?

That BMW TB connector has also had many issues in the past, I wouldn't expect pins on both circuits to fail at the same time, and when they do it is usually intermittent, but there is a connector lead available as a service part.

Check what voltages you get on TV1 and TV2 with the TB disconnected.
 

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Discussion Starter #13
I got BMW kit for the new throttle body with wires, clipped the old connector off installed new one and it did not change. Next I fished each individual wire out of the harness back to the ECU and instpected wires. Having the TB disconnected and looking at my scanner TPVS #2 goes to 0, TPVS #1 actually goes up to 5. I pulled the 52 pin connector off of the ECU to inspect the connector and it seems ok.

Also with the TB hooked up and key on I disconnected the ground (blue wire to pin 5 on TB) and on the scanner both TPVS #1 & #2 go to 5.0 like they both are an open circuit. Based on that it seems like the wire for the TPVS #1 (purple wire to pin 1 on TB) from the computer things it doesn't have a ground.

Thoughts

TB Pin out
#1 Purple TB Sensor signal #1 to pin 24 on 52 pin connector to ECU
#2 Brown/Red TB Sensor signal #2 to pin 8 on 52 pin connector to ECU
#3 Brown Throttle pos sensor ref voltage to pin 10 on 52 pin connector to ECU
#4 White Throttle Pos Actuator #1 to pin 42 on 52 pin connector to ECU
#5 Blue Throttle Pos Ground to pin 25pin to ECU
#6 RedThrottle Pos Actuator #2 to pin 45 on 52 pin connector to ECU
photo.JPG
 

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Discussion Starter #15
RoverGuy7, this might come out wrong but I think I might love you! This has been nearly the death of me for a few weeks. Thank you for putting me on the right track!
 

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I have exact same problem. Rough idle. No throttle control. Throttle body turns on then trips as soon as peddle is touched. Throttle body and pedal replaced. Thermostat connector had some corrosion but nothing at ecu end.

The blue wire seems to have continuity to the engine. All other wires buzz through correctly.

Seemed to happen after leak at back of engine too!
 
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