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Wrecked Outback in limp mode
I recently bought a wrecked 2015 Subaru Outback Premium with eyesight and replaced all damaged parts with new OEM Subaru Parts or used stock parts. The vehicle was hit in the front left side and had no airbag deployment. A few of the wires in the wiring harness to the headlight, fog light, and horn were damaged and repaired by twisting 1" overlapping strands and using a good solder, then shrink wrapping. The foglight ballast was smashed and replaced as well as the headlight. All the voltages seem correct and all the grounds seem good. All the lights work as they should. The front a-arm, strut, and axle were also damaged and replaced. And the ABS sensor was replaced just because. There was no actual frame damage only support pieces and suspension.
After reassembly the vehicle is in limp mode with all the dash lights on. The codes i am getting are p0500, powertrain speed sensor, and three historic faults of P2158 powertrain speed sensor B, U0122 network, U0284 network.
Several times upon starting the vehicle has had no issues, no lights, and drove fine, then upon restarting it will be back in limp mode.
What I have tried.
I have reset the ECU, left the battery off for long periods of time with the entire ECU disconnected, then turned the key on without starting and the codes are back instantly. This is leading me to believe it is an electrical issue and not actually related to the drivetrain.
I have checked the voltage on all effected wires and moved the harness around while checking to see of there were any more breaks. I also checked the resistance on all the ground wires and everything seems good.
I am leaning towards replacing the whole harness but I don't want to do that if its not the issue.
I have attached some pics just because, still waiting on the front bumper to get here then paint.
After reassembly the vehicle is in limp mode with all the dash lights on. The codes i am getting are p0500, powertrain speed sensor, and three historic faults of P2158 powertrain speed sensor B, U0122 network, U0284 network.
Several times upon starting the vehicle has had no issues, no lights, and drove fine, then upon restarting it will be back in limp mode.
What I have tried.
I have reset the ECU, left the battery off for long periods of time with the entire ECU disconnected, then turned the key on without starting and the codes are back instantly. This is leading me to believe it is an electrical issue and not actually related to the drivetrain.
I have checked the voltage on all effected wires and moved the harness around while checking to see of there were any more breaks. I also checked the resistance on all the ground wires and everything seems good.
I am leaning towards replacing the whole harness but I don't want to do that if its not the issue.
I have attached some pics just because, still waiting on the front bumper to get here then paint.
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Could be one or more intermittent connections or wires in the system: unplug and reinsert everything connected in the network where you can. Perhaps something got jarred loose in the collision that isn't visible to the naked eye.
Another possibility is something on the bus is acting sporadically in what it puts out on the bus: the question is, if that's the case, if there are things you can leave unplugged and still run the car at all, or not in limp mode.
Another possibility is something on the bus is acting sporadically in what it puts out on the bus: the question is, if that's the case, if there are things you can leave unplugged and still run the car at all, or not in limp mode.
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I disconnected and reconnected every connection I could find with no luck. I also tried disconnecting things and starting the vehicle to see if any of the sensors or system were causing the bus problems like you mentioned with no luck. Do you think a better OBD2 reader or computer would have better luck? Right now all I have is torque pro.
At this point, it may be simpler to replace the harness and see if things resolve: at least you'd have a solid idea the harness isn't the problem. I realize that's going to cost, but I'm not sure that there's a more reasonable solution other than substitution with known-good parts. The problem with intermittent parts is they'll often behave ok when not under stress during testing with ideal conditions, but fail when in actual use.
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Some ideas . . .
P2158
An incorrect left front wheel speed sensor signal could be causing the P2158, and that could be related to the replacement ABS sensor, or its wiring. P2158 is triggered if the speed signal from the left front wheel is equal to or above 186 mph for 2.5 seconds or more. In this regard, the sensor picks up a signal from a magnetic ring embedded in the back of the wheel bearing hub. If the magnetic ring was damaged, it could be causing an abnormal ABS wheel speed signal.
U0122 LOST COMMUNICATION WITH VEHICLE DYNAMICS CONTROL
MODULE
The VDC control module and the ABS control module work in tandem. This code, and the P2158 might be related to the same problem. In this case, wiring/connections to the control modules.
U0284 Lost Communication With Active Grille Shutter Module "A"
(Good chance wiring to the shutter was affected by the collision and/or the work involved in the repair. The communications is between the ECM and the shutter control.)
P2158
An incorrect left front wheel speed sensor signal could be causing the P2158, and that could be related to the replacement ABS sensor, or its wiring. P2158 is triggered if the speed signal from the left front wheel is equal to or above 186 mph for 2.5 seconds or more. In this regard, the sensor picks up a signal from a magnetic ring embedded in the back of the wheel bearing hub. If the magnetic ring was damaged, it could be causing an abnormal ABS wheel speed signal.
U0122 LOST COMMUNICATION WITH VEHICLE DYNAMICS CONTROL
MODULE
The VDC control module and the ABS control module work in tandem. This code, and the P2158 might be related to the same problem. In this case, wiring/connections to the control modules.
U0284 Lost Communication With Active Grille Shutter Module "A"
(Good chance wiring to the shutter was affected by the collision and/or the work involved in the repair. The communications is between the ECM and the shutter control.)
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Ill order one and give it a shot. I just have to figure out which of the 12 bulk head harness part numbers listed for this car is actually the right one.
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I ran the old ABS sensor for a little then ordered the new one thinking that may be the issue. Neither sensor made any difference. And the old sensor was showing voltage at the connector when the wheel was manually spun so it probably was not bad. I also cleaned the magnetic ring in the hub/checked for damage. What makes me think that is not actually the issue is that it throws those codes after an ecu reset before the vehicle has been started or moved. The shutter seems to be working correctly, I manually closed it and it opens when I turn the key.
When the car decides to go out of limp mode every code goes away at the same time. Which would seem like it is one thing causing all the issues.
'16 Outback 2.5i Premium WAM, Factory Hitch, Infinity speakers, Alpine Sub, Cargo Tray/Seat Protectors, Husky Liners, Rally Armor Mudflaps, LED Int Ltg, Subaru LOGO LED Projection Puddle Lights, OUTB
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A better OBDII reader or better software tailored for your OB will be best. With the same ECU tester used by dealers, you can check each sensor for proper values. It will help you diagnose which device is faulty.
I would suggest taking the vehicle to your nearest Subaru dealer and have them put their tester on and find out which device is at fault. Ask for their most savvy ECU tester technician, which might be the one right out of school, or some old-timer who knows his stuff. They know who it is and you should be willing to wait on that tech's schedule.
You can also ask around for any Subaru tuner's in your area. These are the people with that same dealer ECU tester, but they can update firmware in the ECU to tune it specific ways other than what Subaru wants. You don't want them to change the firmware, but that tester they use, might be cheaper than the dealer's tech doing the same job.
Was the battery broken in the wreck ? If so, the acid got into the wiring on that side. It is very possible that you will have electrical problems. I would replace the harness if other ideas offered above do not work.
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