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WagonDad |
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Can any one give a bit more detail about this 511 ECU Failure-hard code. Speedo and odometer have stopped working, auto is in limp home mode, I have replaced the speed transducer, tried another cluster and manually turned the transducer with a drill and still no luck. So it looks like either a wiring break/fault or the ECU playing up. The speedo will come back to life every now and then and the auto will go back to normal, but this only seems to happen when I put my foot down and accelerate harder, any one had similar problems.
Thanks.
_________________ 4.0L EF Fairmont Station Wagon. EL GT Snorkel. K&N Pod in air box. 3" Intake piping.
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snap0964 |
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Well the good book only says an internal ECU failure for code 511 - no surprises there. Although I'd suspect it's caused by something external maybe.
As you say, sounds like an intermittent feed of the speed sensor output. I'd suggest a continuity check from the speed sensor to the instrument cluster, then from the cluster to the ECU plug (white line). Then for the red line from the SS to the cluster. Then check the black line at the SS plug has a good earth (probably do this first). Check the connector plugs - near the SS, the inst cluster, and the ECU plug - I have found with connection issues where the wiring is okay, to slightly bend the male pin to get a better connection. How's the drive gear in the back of the g/box look - get a torch and a mirror and have a bo peep. What's the driven gear on the SS like ?? Is the clip seated properly, etc ?? It could be an ECU issue, somehow I doubt it, but borrow another EF I6 one and try it.
_________________ 96 XH Longreach 'S': LPG, Alarm, 3.23:1 LSD, Cruise, Trip Comp, ABS, Power Windows, Mid Series Dome Lt, Climate Ctrl |
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66 coupe |
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{USERNAME} wrote: The speedo will come back to life every now and then and the auto will go back to normal, but this only seems to happen when I put my foot down and accelerate harder, any one had similar problems.
Thanks. Quite possibly a bad earth somewhere, loading up the engine puts more stress on the driveline allowing it to earth (possibly through the diff - this was common on XF taxi's and used to pitt the crownwheel and pinion) |
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WagonDad |
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Thanks guys, Bad earth sounds the most likely, where should I be looking for earth points. I have checked the drive gear by sticking my finger in the hole and moving the car back and forward, the cog turned and had all its teeth. I have checked the plug closest the speed sensor by probing the wires either side, all completed a circuit. Thanks for the help.
_________________ 4.0L EF Fairmont Station Wagon. EL GT Snorkel. K&N Pod in air box. 3" Intake piping.
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66 coupe |
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earths - battery to body and battery to engine block are the main ones, easiest way to check is start the engine, put rear demist, headlights and high beams on and measure the voltage between the negative battery terminal to the body and negative battery terminal to the engine block, both ideally should be no more than 0.2 volts.
If you still have no luck, then you may need to check the cluster in more depth as this is the first termination point of the speedo signal. Do all the other gauges in the cluster work, and just the speedo that is not? |
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snap0964 |
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NP. The earth is the easiest to check - check the black line on the SS connector to the chassis, e.g. maybe use the rear trans crossmember mounting bolts. Also try for continuity from the plug to the transmission case (this will earth through the engine block earth). You may need to use a bit of emery cloth to get clean test points - I'm pretty sure this is a chassis earth, and not a signal earth (there is a difference).
With the signal line, I forgot to add that the line to the cluster, and the line to the ECU are different pinouts (check the inst cluster doco). Edit: If you do have a wiring issue, all 3 speed sensor lines (power, signal, earth) go up though a rectangular plug behind the BBM before entering the passenger side firewall (IIRC).
_________________ 96 XH Longreach 'S': LPG, Alarm, 3.23:1 LSD, Cruise, Trip Comp, ABS, Power Windows, Mid Series Dome Lt, Climate Ctrl |
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WagonDad |
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OK, just pluged the old speed sensor in, cut the insulation back on the black wire and earthed this back to the cross member and still no movement on the speedo, should that have worked if it is a earth problem. Every thing else on the cluster works only the speedo and odometer are the problem. I replaced all earth cables and added a few extra about 4 months ago, I thought there might be specific earths for the wiring harness other than these.
_________________ 4.0L EF Fairmont Station Wagon. EL GT Snorkel. K&N Pod in air box. 3" Intake piping.
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66 coupe |
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ignition on, there should be approx 8 volts on the signal wire at the transmission, and also 12 volts on the power feed to the speedo sender.
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WagonDad |
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The speedo is now working, and the only reason I can give is giving the wiring harness a good move around trying to find out where all the wires ran. Obviously I have a connection or wiring failure and need to check the continuity of the wiring from the speed solonoid to the cluster, something I'm not to sure on but as Iv'e learned persistance and asking questions generally solves most problems. Thanks for your help guy's.
_________________ 4.0L EF Fairmont Station Wagon. EL GT Snorkel. K&N Pod in air box. 3" Intake piping.
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snap0964 |
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{USERNAME} wrote: The speedo is now working, and the only reason I can give is giving the wiring harness a good move around trying to find out where all the wires ran. Obviously I have a connection or wiring failure and need to check the continuity of the wiring from the speed solonoid to the cluster, something I'm not to sure on but as Iv'e learned persistance and asking questions generally solves most problems. Thanks for your help guy's. NP. Do take on board the answers you get back as well - I wondered by a couple of your replies whether you listened to us, as using the original SS and earthing it was a bit of a sideways step. In addition to what I've posted, most wiring faults will occur at connectors, or areas where the loom may be exposed, or going through panels, etc. Do your continuity tests from the cluster plug and use a needle to the wiring at the back of the SS. If you get opens, then go to the rectangular plug to the SS, then the SS loom connector.
If no problems (wiggle wiring as well), look at the cluster plug connection as covered earlier. It may just be a case of unplugging and replugging connectors. Anyways, good practice for you.
_________________ 96 XH Longreach 'S': LPG, Alarm, 3.23:1 LSD, Cruise, Trip Comp, ABS, Power Windows, Mid Series Dome Lt, Climate Ctrl |
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Aces_Inc |
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WagonDad |
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Thanks again guy's for the replies. Hey snap0964 Im sorry if it came across like that, the written word can often be misconstrued or taken in the wrong vain. As for checking all connections in my previuos posts I said the cluster had been out and another was tried the connections would have been unplugged and plugged back in, I also said I had checked the connection closest to the speed sensor and it was good, the only connection I hadn't checked or unplugged was the one you pointed out behind the BBM, which I did check, sorry for not telling you about that. As for the the way I eliminated the possibility of an earth problem it was the best I could come up with considering my inexperience with auto electric's, achieved the same result, who cares. Sorry if this offends you, just replying to a comment that I think was misplaced.
_________________ 4.0L EF Fairmont Station Wagon. EL GT Snorkel. K&N Pod in air box. 3" Intake piping.
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snap0964 |
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Nah, no issues here - just trying to steer people in the correct direction, and save them some work at the same time. It is hard to advise people when you aren't physically there - you need to rely on their feedback.
The main concern I had was whether you were testing using an earth that was tested as reliable, otherwise you can very easily confuse yourself, and get frustrated as well. Don't read too much into it either. The other thing I try to do is make people think as well, this way they learn more. Do be wary though - plugging in different items into a particular plug doesn't rule the plug out, even though the components are okay. Seen this quite often, e.g. with trip computers, and a CC unit, in both cases, the items being plugged in were fine, wiring checked out okay, fault was a dodgy female pin. It all comes with practice and experience.
_________________ 96 XH Longreach 'S': LPG, Alarm, 3.23:1 LSD, Cruise, Trip Comp, ABS, Power Windows, Mid Series Dome Lt, Climate Ctrl |
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