1. DEUTSCHES ALLRAD-FUSO FORUM
24. Mai 2022
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Hello everyone i have a code PO627 fuel pump control circuit permanent and i can not erase the code. the problem in current. the fuel pump runs and no light on the dash. at times the pump will not run at all or start the engine. i have checked most of the items listed but still have this code.
- Replace a defective fuel pump/ New pump on order
- Replace a defective fuel pump relay/ swapped from a other relay
- Replace or repair any electrical components in the CAN Bus harness, like wiring or connectors, that are corroded, open, or short
- Adjust a loose control module ground strap/ checked and cleaned the grounds.
- Replace a broken control module ground wire/ check grounds
- Replace a defective CAN Bus/ CAN BUS WORKS WITH THE SCAN TOOL.
- Repair a poor electrical connection in the fuel pump circuit/checked ohms to the fuel pump ok
- Replace or repair an open or shorted fuel pump harness
- need help to find this problem with out replacing control units and guessing. thanks everyone.
26. November 2016
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Ernest ?,
could you support with Motor Code (e.g 4P10) and the dtc code from Meter (including the FMI) ? That would help.
Do you have RED/Amber/Yellow lamp warnings ?
.......... Some DTC background which could get a hope .............(i own a TF1 Canter 6C18D so all is based on that ....)
Genericaly the PO627 (Open circuit) means that the observing ECU (in this case probably the Motor Control Unit or SAM control Unit) "see" an open line.
You say the fuel pump run - Always Regardless of ignition status (Accessory/run/off) ? => normaly pump shall stop running (listen noise) after ~30sec from key off. Please check and report.
If pump starts/stops according key's position => The ECU (in this case the SAM, B40) is able to drive the pump physically.....
If this is the case, the recognition of the pump's current migtht be out of range.... A electronic monitors the current and decide if it is "in range" or out => the a "openload" is detected. So with a plenty of bad luck, false openload can be detected. Especially when pump itself run on low current by variation (natural manufacturing issue). So with high sensitve SAM and low current pump it might happen that you have false detection.
Also some aftermarket pumps might draw to less current for proper recogntion.
However on openload the outputs stay actuated, because this is the safe state, perhaps detection "catches" normal value again.
This behaviour is described in the Error Set and Unset conditions more detailed.
If you want to measure professional, you might messure Current flowing into pump and voltage to the pump. (Terminal 4,3 of pump connector) Volatge you can tap with sharp tips on multimeter directly.
Also check if pump stops running when removing the fuse for the fuel pump (this is for my point the best solution to measure the current to the pump by the way )
Unplug the F34 (15A) fuse and apply current meter in place of fuse and report the current you see there.....
If it helps take a broken(!) fuse and solder wires on it (or blow the fuse for the sake of testing 😉
You cant change the detection levels in the SAM ECU, they are not all coded.... If above is the case a parallel resistor (more load) to the pump might help.
Hope it helps
Daniel
24. Mai 2022
Offline
danieldd sagt
Ernest ?,could you support with Motor Code (e.g 4P10) and the dtc code from Meter (including the FMI) ? That would help.
Do you have RED/Amber/Yellow lamp warnings ?
.......... Some DTC background which could get a hope .............(i own a TF1 Canter 6C18D so all is based on that ....)
Genericaly the PO627 (Open circuit) means that the observing ECU (in this case probably the Motor Control Unit or SAM control Unit) "see" an open line.
You say the fuel pump run - Always Regardless of ignition status (Accessory/run/off) ? => normaly pump shall stop running (listen noise) after ~30sec from key off. Please check and report.
If pump starts/stops according key's position => The ECU (in this case the SAM, B40) is able to drive the pump physically.....
If this is the case, the recognition of the pump's current migtht be out of range.... A electronic monitors the current and decide if it is "in range" or out => the a "openload" is detected. So with a plenty of bad luck, false openload can be detected. Especially when pump itself run on low current by variation (natural manufacturing issue). So with high sensitve SAM and low current pump it might happen that you have false detection.
Also some aftermarket pumps might draw to less current for proper recogntion.
However on openload the outputs stay actuated, because this is the safe state, perhaps detection "catches" normal value again.
This behaviour is described in the Error Set and Unset conditions more detailed.
If you want to measure professional, you might messure Current flowing into pump and voltage to the pump. (Terminal 4,3 of pump connector) Volatge you can tap with sharp tips on multimeter directly.
Also check if pump stops running when removing the fuse for the fuel pump (this is for my point the best solution to measure the current to the pump by the way )
Unplug the F34 (15A) fuse and apply current meter in place of fuse and report the current you see there.....
If it helps take a broken(!) fuse and solder wires on it (or blow the fuse for the sake of testing 😉
You cant change the detection levels in the SAM ECU, they are not all coded.... If above is the case a parallel resistor (more load) to the pump might help.
Hope it helps
Daniel
Hello Daniel thank you for help with this code. I have the 4P10 engine. the fuel pump runs when the ignition is on and off for 30sec. the amps is 5.5 amp at the SAM control unit at the fuel pump relay. But at times it will not operate i would remove the connections at the EPC control unit. I have no check engine light on. only a permanent code po627 and a second code just added P0087 low fuel pressure ONLY after the pump stops running. I will need to drive it to see if it drives normal.
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