Subaru dash lights

Michael Technician New Hampshire Posted   Latest  
Resolved
Driveability
2015 Subaru Outback 2.5i Limited 2.5L (FB25) (TR580) — 4S4BSBNC9F3267125
P0441 — EVAP System Incorrect Purge Flow
P0455 — EVAP System Leak Detected (large leak),
P1604
Cel
Brake Light
Traction Control Light

The car came in with the CEL light on, traction control, Brake light flashing, Eyesight message and several others. I scanned the car, and came up with faults in 13 systems, but only a couple faults as active. the systems affected are;

ECM, LT (headlamp,foglamp) AC, IPC, BCM, Seat, ES (Eyesight) ABS, ESP, RH (right rear detection) LH (left rear detection)OCPT(occupant detection) and TPMS.

The car runs fine, and drives fine. 

The codes in the ECM are listed as pending and history. 11 IPC codes (communication codes, all history, BCM codes are all history

I do have them listed, but my question is about where to start. The customer states they started the car, and all those lights were on. As it was late Friday, Other than scanning, I did check the battery, and alternator, and did voltage drops on the ground I found in the engine bay. A quick visual look shows no rodents living in the car, chewing stuff.. Where to start the actual diagnosis is the question. Would an engine code effect all these systems, or the other way around? Would a instrument cluster be the area to start.

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Interesting
Glenn Owner/Technician
Texas
Glenn
 

Hi Michael, I guess I am old school about strategy, but it has worked for me. Take one code at a time starting with the lowest number on a system and track it down. I find that very often the higher number codes will correct. Go with the hard codes, don't chase history or pending until they become hard codes. Document and clear all system codes, then perform a full test drive cycle 2 times…

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Agree
Robert Diagnostician
California
Robert
 

Did Subaru hire a Toyota engineer? Toyota loves to turn on the traction light and others when it sets an EVAP code. Had 2 last week. LOL! Other than that I would check voltages when starting (battery load test with a real carbon pile tester). Since the problem happened right after a start I would suspect a weak battery.

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Paul Mechanic
Illinois
Paul
 

It's been my experience that any time the cel is lit, traction/stability is disabled as it is directly connected to engine performance. Like if base brake system has issue, abs is disabled. I know gm disables remote start if any DTC on pcm is active.

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Robert Diagnostician
California
Robert
 

How does an evap leak change engine performance? Gas cap loose? I know they have to disable stability control when engine performance or emissions would be changed by reducing power output. A loose gas cap? really!!!!!!!!!!!!!!! I get the feeling that the engineers did now want to make those distinctions at Toyota like other manufacturers.

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Paul Mechanic
Illinois
Paul
 

It's just my observation-don't necessarily agree with it. An EVAP leak or inefficient cat should never effect engine performance, but from a liability stand point, the engineers probably don't want to go through the distinctionn of which codes in the PCM allow or disable traction/stability.

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Jamie Mobile Technician
British Columbia
Jamie
 

If you can post your full vehicle scan showing all the codes, this would help to help you figure out where to start. As I'm sure you know, a lot of these systems are interconnected.

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Glenn Owner/Technician
Texas
Glenn
 

Hi Jamie, We need the whole story. What are the the full code lists?

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Michael Technician
New Hampshire
Michael Update
 

So I spilt coffee on my list, so had to reprint it today at work. Here is the list; ECM- P0441, Incorrect purge flow Pending. P0455 Large Evap Leak History. P1604 Startability malfunction History. ABS- C1422 VDC interruption for engine History. IPC- B1502 Warning box communication History U0100 Loss Comm with ECM History. U0101 Loss Comm with TCM History U0122 Loss Comm with dynamic control…

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Jamie Mobile Technician
British Columbia
Jamie
 

Thanks for posting your scan. I see a few codes that are current and the rest are history. Unfortunately, we don't know when the history codes set. Lots of loss of comm codes which could be due to a previous low battery or communication bus fault (all modules are on the same CAN bus on this vehicle). I'd set those aside for now and focus on the current faults. I'll comment on the non-engine ones…

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Geoff Diagnostician
Hawaii
Geoff
   

When I see a bunch of comm codes, tattle-tail codes, and voltage codes, I want to re-interview the customer about how long the car sits, and give that battery a good old fashioned LOAD test. As for a EVAP leak code and a purge code--- pretty good odds the purge leaks some days.

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Rudy Technician
Utah
Rudy
 

Personally, Id start by looking at OBD2 an documenting the codes there. Only those codes are turing on the MIL. Those are the only codes Id address for now. Print out or documnet the rest. Troubleshoot the OBD2 codes then clear the rest.

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Michael Technician
New Hampshire
Michael Resolution
 

It's been a week or so, and the customer opted to shotgun a purge valve at the car, and take it. I found out this morning the customer is apparently happy with the car, and no return lights or issues. They've drive about 650-700 miles, so I'll call this closed with no real solution. Thank you for all the help and information!

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