PCM power relay Diagram?

2012 ROVER RANGE ROVER
16,543 MILES • 2.0L • 4 CYL • TURBO
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ANDRIN ATEM
IBM wiring diagram, also the pcm relay power supply diagram.
Mar 13, 2026 at 6:44 AM
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AL514
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Hello, Im getting the ECM diagrams together, for the IBM, are you referring to the Battery monitor module?
Mar 13, 2026 at 7:59 PM
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AL514
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These are the aftermarket and oem wiring diagrams for the ECM module relay. the 3rd diagram is the factory oem diagram.
Mar 13, 2026 at 8:20 PM
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AL514
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Are you getting specific codes for anything?
Mar 13, 2026 at 8:21 PM
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ANDRIN ATEM
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Yes, I will update you the codes
Mar 13, 2026 at 11:00 PM
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ANDRIN ATEM
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Check these codes
Mar 13, 2026 at 11:04 PM
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AL514
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Well I can see the first code on the list (P068A-00) being the cause of the other codes setting. Low voltage to one or more sections of the ECM can cause all sorts of circuits to read inaccurately. Thats the the one I would diagnose first.
Heres some service info to go with the ECM power relay code. That area, including the fuse box where that relay lives are suspect. Many of these fuses boxes have power bus bars all soldered together and they can crack internally causing intermittent issues due to thermal expansion of cracked solder.
The diagrams above still apply. You need to monitor that relay and see if its de-activating too early or maybe not at all. I would monitor the ECM's input voltage levels using more than just a scan tool. While looking at live ECM data you can compare your readings with a multimeter and what the scan tool reads to find discrepancies, always back up your scan tool data with another source, ie a multimeter, oscilloscope, etc.
Let us know what you find.

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

https://www.2carpros.com/articles/how-to-use-a-voltmeter
Mar 14, 2026 at 12:03 PM
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AL514
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Also note, bad Grounds can cause codes like this to set, voltage drop testing on both the ground and power side of the vehicles electrical system can reveal hidden problems.
Mar 14, 2026 at 12:19 PM
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ANDRIN ATEM
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Thank bros, I let you know what happens.
Mar 14, 2026 at 4:40 PM
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AL514
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Glad to help. Hope you find the issue pretty easy. A 2012, and if that mileage is correct, that means this vehicle sits a lot. That points to water intrusion, corrosion, and/or rodents getting in and chewing wires, they love to eat the insulation on the wires because its sweet to them. So focus on wet interior areas and bulk connections, etc. But we'd like to hear what the remedy is when you get there.
Mar 14, 2026 at 6:27 PM
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