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2006-2009 Range Rover MkIII / L322
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Discussion Starter · #1 ·
Anyone have a connector diagram for the larger of the two ECM connectors in an 06 4.4L HSE? I'm trying to trace my ignition coil feedback wires back to the ECU from the coils and can't even figure out which pin is connector 1, let alone the ones I need to check continuity from the coils to the ECU. I started out with no continuity for the feedback wires between coils 2,3,5, and 8 (the 4 feedback circuits for these 4 coils are spliced together somewhere in the harness) and a single wire runs from that splice to the ECM so the engine knows the coil has fired . Now after pulling apart the wiring near the ECM I've magically got continuity back between the coils, but can't find the pin on the ECM connector that goes with it (its pin 64 supposed to have a yellow with black stripe wire on it). I've found a few like that but theres more than a couple of similar colored wires in the connector. I need to make sure that have continuity between the coils all the way back to the ECM. 06-09 will work, as will the connector for a sport of similar years. Maybe even LR3's and 4 might be the same.
 

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2010-2012 Range Rover MkIII / L322
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Mark,

The thinner yellow/black and yellow/brown are typically the twisted pairs for the CANBUS circuits.

I’m away on a trip until late Tuesday but will try and look for a wiring diagram when I return if you haven’t already solved your issue by then.

Rob
 

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Discussion Starter · #3 · (Edited)
Thanks, I have the wiring diagram for the circuit, just can't find where the wires go on the big 96 pin connector on the ECU I know I'm looking for pin 64 but can't figure out which one it is, none of them are marked on the connector and theres several yellow with a black tracer on them. Not all the pins are used, but theres a ton of them. I need one of those pictures of the face of the connector showing me the pin numbers.

I think the can bus wires come into the smaller of the two connectors on the ECU, theres some twisted yellow and black and yellow and brown wires on that connector connected to neighboring pins..

I'm checking for continuity from the coils back to the ECU but if the wire is broken I can find it that that way, and I've been thru most of them at this point. I think I've found the wire but theres no continuity between it and the coils and I really don't want to strip open the harness along the top of the right side of the engine yet till I know that I'm on the right pin and its a wiring issue and not a fried ECU input.

This is what the ECU looks like, its different thant the 2000-2005 BMW engined vehicles which do have the nice connector face pictures in their electrical supplements. The 06-09's don't have that info (of I haven't found it yet);

294579
 

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L322 - 2005, 2006 na, 2012 sc
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Mark, does this help? It looks like the coils to the ECM are pins 54-62 & 64. I don't have a pinout but usually it's left to right, top left is #1. Using the colors below should help locate the correct pins. The connector has 96 pins on it. I could not find pin #1 being used. Pin #2 is brown (ground). Pin #96 is White w/Red tracer. This is for a 2006.

294580


Wire Colors codes. The diagram above doesn't exactly show the colors very well - ie. the top left wire C0634-61 is listed as color "GU" - Green w/Blue tracer.
294581
 

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Discussion Starter · #5 ·
Yes I was looking for pin 64 on the larger connector and finally found it by compairing the colors of the wires around it. I do have continuity all 4 of the bank 2 (thats what they call it, not the same as engine bank 2) ignition coils to that pin, so thats not my issue (maybe). I put it all back together and I have no pending codes yet (about 5 minutes of run time) usually they pop right back up on start as pending. I'm about to make an hour trip each way so hopefully they won't comeback. I cleaned all the coil connectors, and the ECU connectors so maybe thats it? Wishful thinking at this point I know. Like I said it doesn't cause any misfires or run weird in any way, I just get the MIL lamp and those P0352,0355, 0358 codes. The only thing I've done is before these codes popped up was to change from NGK Iridium to Denso TT Iridium plugs, but they shouldn't have anything to do with circuit fault signals to and from the ECU and then why would only 4 of 8 cylinders be doing that?.
 

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Discussion Starter · #6 ·
The MIL light came back after about 10 minutes of run time and 3 start stop cycles, seems to come back when the engine reaches normal operating temp. Was fine up till it reached about 190F. Time to break out the oscilloscope to check the voltage pulses coming from the coils to the ECU, and maybe find the ground connector for these coils primary power circuit and clean it up.
 

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Mark, if you still have your old plugs suggest swapping them just to rule that out.
 

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Discussion Starter · #8 · (Edited)
I do still have them all labeled for what cylinder they came out of, will probably give that a try this weekend along with swapping the coils all around to see if the codes follow the coils. There are counterfeit plugs out there (who knew) but I still can't see how that would affect the codes I'm getting which is specific to one group of feedback wires. Basically the ecu is telling me 3 of the 4 coils in ignition group 2 are not firing, even thought the truck has never run better (as far as mileage anyway) since the swap. The ECU sends out a 5V trigger signal to the coil, and once it fires the coil sends back a voltage signal to the ECU to say it has fired. These return signals are grouped into two ignition feedback circuits for cylinders 1,4,6,7 and 2,3,5,8. by using the crank position sensor the ECU figures out which cylinder is firing or not, and gives you those P035X (X = cylinder number) codes. The power and ground circuits are all commoned up at the source and ground points, if you loose one of those then the coil will not fire and you will get a P030X misfire code, but probably not the P035X circuit code. Since the only part of the circuit that is all jumped together (and matches 3 of the 4 cylinders in one group) is the feedback to the ECU. I checked continuity of the 4 feedback wires from the coils to the ECU and all 4 in this group are continuous so it got to be something at the end of the circuit, like the coil or the ECU input (and yet it still knows cylinder 3 which is in the same group is firing). I have till August to figure it out because thats when the truck needs to be inspected, and it seems to be running just fine, except for the MIL light.
 

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I'll bet you a virtual beer once you swap the plugs back the problem goes away...
 

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Discussion Starter · #10 ·
Heres some weirdness. I swapped all the spark plugs back to the original NGK Iridiums on the RH bank of the engine, cylinders 1,3,5, and 7 (all I had time for between working today) didn't change any on the LH bank cylinders 2,4,6,and 8. Codes before were P0352, P0355, and P0358. Current codes are P0354, P0356 and P0357. Since 7 was on the bank I just changed the plugs on I also swapped a spare coil in that cylinder, and the 0357 code remained. Apparently these engines/ECUs don't like the twin tip Delco TT Iridium plugs. These aren't any fancy plug the twin tip part is just a small Iridium pin on the ground electrode, so instead of arcing from the center iridium electrode to a steel ground electrode, the arc jumps between two thin Iridium pins which don't wear away. Still don't understand WTF is going on with these because the resistance of the Denso TTs is within a couple of hundred ohms of the NGK plugs. I measured them both as the TT's came out and the NGKs went in. The lowest NGK was 3760 ohms, the highest 4030 ohms. The lowest TT was 3930 ohms, and the highest was 4540 ohms. Generic specs for either plug is 5K ohms. Looks like I may owe you a virtual beer before this is done.
 

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Discussion Starter · #11 ·
Replaced the other 4 plugs with the originals and guess what? The codes are gone (at least after 5 run cycles). Someone is going to have to explain to me how changing plugs with a set that on the surface seems to be almost electrically identical and well within the generic ratings for a resistor plug can cause the ECU to produce ignition coil circuit fault DTC's for one of the two feedback circuits while running essentially perfectly. Just in case no one has seen a Denso TT plug here's a crappy picture of the twin Iridium tips on the plug.

294639
 

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Glad to hear it's fixed! I think the Denso should give you an explanation, along with a refund :)
 

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Discussion Starter · #13 · (Edited)
I don't think its fixed yet, after driving it today I've still got the P0351,0354,0356, and P0357 codes as being pending, they came back first o354, 0356 and 0357 and then 0351 popped up about 5 minutes later. Hasn't turned the MIL on yet but probably next drive or two it will pop back on. It's odd that this is the codes for the opposite coils that I started out with.

I'm beginning to think I've got one ignition coil with the feedback circuit either shorted to ground, or shorted to power, since the ECU can't tell which cylinder in the group has the problem. The ECU would see either 12V or ground all the time on the feedback circuit instead of a voltage pulse when the coil fires and not be able to figure out which coil it is coming from, so it gives me the circuit DTC for all of them. When I swapped the right bank plugs I must have moved that bad coil from either cylinder 3 or 5 to cylinder 1 or 7 and thats why the fault code changed from one bank to the other. I then swapped the cylinder 7 coil with another spare I had and the codes remained, so if its a bad coil it must be on cylinder 1. I will swap that coil out today and see if the codes go away.
 

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Discussion Starter · #14 ·
Thats what it was, I had some kind of a high resistance short between the +12V terminal (pin 1) to the primary coil, the ground connection (pin 4) and the feedback connection to the ECU (pin 3) on the coil on cylinder 1. So while the coil still worked to produce a spark, the continuous 12V leakage onto pin 3 must have been masking the individual cylinder feedback signals to the ECU so it could not identify an individual bad coil, or wiring so it gave me codes for all 4 of them. A good coil measures 48K-50K ohms between pins 1 and 3 and slightly more between 1 and 4 (mine measured 3840 ohms and 4780 ohms respectively.

Swapped a good coil in and the pending codes immediately disappeared and hopefully won't be back. Now I can put my new plugs back in since it apparently wasn't their fault just a coincident coil failure.
 
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