R55 R55 JCW No Fuel Pump Signal
#1
R55 JCW No Fuel Pump Signal
Hi everyone!
I'm looking for some information or at least some verification in diagnosing a problem with the fuel pump on my 09 R55 JCW. I determined the fuel pump is not getting B+ voltage.
Ultimately, I'm trying to resolve a crank but no start condition. The Tach does move when attempting to start, Ignition system delivers signals to the coils, but the fuel pump does not get +12V.
I saw others had problems with the Junction Box Electronics (JBE), aka fuse box (in passenger foot well). So I removed it and inspected it for any broken solder joints, which appears to be a common problem. Additionally, the JBE does not have any water intrusion or corrosion on any connectors. I also had the fuel pump relay in the JBE replaced. Afterwards, the JBE was reinstalled and I tested for fuel pump signal. It still comes up missing.
I use the Bentley manual to diagnose this problem and I have a few questions (to follow below). I performed the DME main relay test on Pg 130-56. Here are my results:
With Ignition OFF, test the following:
1. Test for B+ at DME Main Relay K6300, Terminal 30 (correspond to Pin 6): +12VDC is present.
2.a. Test for Ground at DME Main Relay K6300, Terminal 85 (correspond to Pin 3): +12VDC is present*.
2.b. If ground is not present, signal from ECM is missing...
* - With Ignition OFF, +12V is present. With Ignition ON, Ground is present. To me, this makes sense because when reading the simplified schematic, the +12V signal runs straight through the relay coil and has no place to go.
As I continued my testing, everything else checked good. The only anomaly is Step 2.a. Did I perform the check correctly? Did anyone else have a similar result? Could someone please confirm this indication? Is ground present at Relay K6300 Terminal 85 with ignition off?
I'm looking for some information or at least some verification in diagnosing a problem with the fuel pump on my 09 R55 JCW. I determined the fuel pump is not getting B+ voltage.
Ultimately, I'm trying to resolve a crank but no start condition. The Tach does move when attempting to start, Ignition system delivers signals to the coils, but the fuel pump does not get +12V.
I saw others had problems with the Junction Box Electronics (JBE), aka fuse box (in passenger foot well). So I removed it and inspected it for any broken solder joints, which appears to be a common problem. Additionally, the JBE does not have any water intrusion or corrosion on any connectors. I also had the fuel pump relay in the JBE replaced. Afterwards, the JBE was reinstalled and I tested for fuel pump signal. It still comes up missing.
I use the Bentley manual to diagnose this problem and I have a few questions (to follow below). I performed the DME main relay test on Pg 130-56. Here are my results:
With Ignition OFF, test the following:
1. Test for B+ at DME Main Relay K6300, Terminal 30 (correspond to Pin 6): +12VDC is present.
2.a. Test for Ground at DME Main Relay K6300, Terminal 85 (correspond to Pin 3): +12VDC is present*.
2.b. If ground is not present, signal from ECM is missing...
* - With Ignition OFF, +12V is present. With Ignition ON, Ground is present. To me, this makes sense because when reading the simplified schematic, the +12V signal runs straight through the relay coil and has no place to go.
As I continued my testing, everything else checked good. The only anomaly is Step 2.a. Did I perform the check correctly? Did anyone else have a similar result? Could someone please confirm this indication? Is ground present at Relay K6300 Terminal 85 with ignition off?
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08-28-2017 05:52 AM