Help With CEL

[CDLehner]

My '16 has around 113k...has had all it's regular maintenance; given me very issues to this point (probably the biggest issue, is I currently have a [slow] leaking oil-pan gasket). But now I've got my first CEL.

I couldn't locate the cable, for my COBB AccessPort...so I took it to AAP and they returned P0303 - Cylinder 3 Misfire and P173400 - Starter Release From The Selector Lever Sensor System

I've Google'd a bit, including this thread https://www.golfmk7.com/forums/index.php?threads/p0303-cylinder-3-misfire.356255/ . I'm not very handy...and as such, am at the mercy of the Dealer or German specialist. I worry about getting ripped-off, with a more-evasive diagnostic...over "bad plug", or "clogged injector". Does the combination, with the P173400 code...point towards anything?

Ugh...I realize this is a tough question, but...can we recommend a course of action? FTR...my symptoms, are very similar to the OP in the thread above:

I clear(ed) it...and it [came] back w/in a week or two, and on idle I can feel very slight vibration/surging at idle only

Thanks

 

[CDLehner]

Maybe I can get some more eyes on this...maybe not, lol.

While I was waiting to deal with the CEL...I started leaking coolant. Slow at first (got a low-coolant light, topped off and took about 2 weeks to return); but then yesterday I got a light...topped off...and by the time I got to work 15 minutes later, the light was back on. Stupidly...I didn't bring the coolant with me; so I topped off with water, just to try and get the car safely home from work. I could tell...the water just went straight through, from the reservoir out of the splash shield.

Driving home...I paid super close attention, to temps; and the weird thing was (and maybe not so weird, as it turns out) temps (both oil and coolant), were seemingly running low. Yes...kinda stuck low, but they moved occasionally (and coolant temp went up, once I was parked at home). Anyway...into the dealer today.

I was very detailed with my service tech, about the symptoms and progression, etc. They're saying dreaded "thermostat housing" (they make that sound like an "enclosure", but it's the water pump/thermostat part...that's an all-too-common failure, right?). $1,700??

I asked "what about the misfire"? They said when they coded it...they did see misfires in the history...but today it was only coding on the coolant. But...they've also got a "carbon cleaning" at $500 on there.

Now...the German specialist, I used to take the car to; they were generous enough, to talk to me about this diagnostic a bit. The Service Manager there, seemed very sincere...and very nice. She said "carbon cleaning is absolutely a thing", but (and mind you...without being able to look at the car; it's still with the dealer)...she would have thought about looking at the coil packs first. For all I know, they (the dealer)...did their due-diligence; I was there for 3 hours, and stunned by the estimate. I didn't press them for some details.

The Service Manager at the German specialist...used to work at the Dealership. She gave me the name, of what she called the "master mechanic" there...and said I should speak with him to follow-up. I plan to...and I'm not going to be one of these "well I read on the internet", or "the guys on my GTI forum said" guys; but...I would like to go in, somewhat educated about what to listen for to keep them honest.

I know...it's kinda a kooky request; like the OP before it. But any feedback and help, to shed light on what they're proposing...is much appreciated. Flying blind here. TIA

 

[tigeo]

Starter select one. Clear it. I've had that one intermittently for a long time. As far as I can tell there are no negative impacts. The other can be a host of things including ignition parts fuel or carbon buildup on the valves.

 

[Acadia18]

At 113k, you probably do need a carbon cleaning. You can play the "move coil packs around" game, but I hardly see that being the issue.

Not saying it isn't leaking (since it's very common), but you could bring a new car into the dealer and they'd say you need your 'thermostat housing' replaced. Pretty sure they just suggest it as recommended maintenance at every interval

 

[Samb]

Hello all,

Need advice please.

Golf R recently had its water pump and thermostat replaced 5 weeks ago, and I’ve driven less than 500 miles since. The coolant level stayed steady until yesterday, when it dropped just below the sensor. I topped it up slightly above the sensor with water to track any further loss.

Within 30 hours (<50 miles), the low coolant warning came back. I noticed the area near the driver’s side headlight, below the washer fluid reservoir, was very wet. Since it’s been raining heavily, I’m not sure if this is a coolant leak or just rainwater. There’s no coolant smell, and the rest of the engine bay is dry. The wetness seems to be much more than the actual coolant loss.

I suspect there might be an airlock because I hear bubbling sounds after switching the car off following a 15-minute drive. The noise is more noticeable when I accelerate hard once or twice during the journey. The car heats normally at lower fan speeds (1-3), but the air turns cooler when I set it to full blast, even with the temperature on high.

The car hasn’t overheated; the coolant temp holds at 90°C, and the oil temp rarely exceeds 107°C. Car seems to be pretty healthy returning 27-29mpg+

The diagnostic scan shows error code “P16C700: Heater Support Pump Locked”.

This code was present before the water pump and thermostat were replaced, but I didn’t have heating problems back then.

Any thoughts on whether this could be an airlock or something else? Also, does this vehicle have a pressurised coolant system and does it need to be driven to clear air pockets? If so, I’ve driven enough for it to have worked itself out by now.

 

[Mksleven]

Hello all,

Need advice please.

Golf R recently had its water pump and thermostat replaced 5 weeks ago, and I’ve driven less than 500 miles since. The coolant level stayed steady until yesterday, when it dropped just below the sensor. I topped it up slightly above the sensor with water to track any further loss.

Within 30 hours (<50 miles), the low coolant warning came back. I noticed the area near the driver’s side headlight, below the washer fluid reservoir, was very wet. Since it’s been raining heavily, I’m not sure if this is a coolant leak or just rainwater. There’s no coolant smell, and the rest of the engine bay is dry. The wetness seems to be much more than the actual coolant loss.

I suspect there might be an airlock because I hear bubbling sounds after switching the car off following a 15-minute drive. The noise is more noticeable when I accelerate hard once or twice during the journey. The car heats normally at lower fan speeds (1-3), but the air turns cooler when I set it to full blast, even with the temperature on high.

The car hasn’t overheated; the coolant temp holds at 90°C, and the oil temp rarely exceeds 107°C. Car seems to be pretty healthy returning 27-29mpg+

The diagnostic scan shows error code “P16C700: Heater Support Pump Locked”.

This code was present before the water pump and thermostat were replaced, but I didn’t have heating problems back then.

Any thoughts on whether this could be an airlock or something else? Also, does this vehicle have a pressurised coolant system and does it need to be driven to clear air pockets? If so, I’ve driven enough for it to have worked itself out by now.

There’s got to be a leak somewhere if you’re losing coolant. Assuming they had topped off/refilled the coolant when they did the job.

Blast your heater on full tilt to promote coolant flow throughout the whole system if you recently had the pump replaced.

I’d consider pressurizing your coolant system to check for any leaks ~ you can rent one of those tools at your local vatozone, I think.

 

[Samb]

I don’t personally believe there’s a leak; I suspect the drop in coolant level might be related to air pockets or bubbling within the system. I could be mistaken, and I’ll certainly have it checked to be sure.

Aren’t these vehicles meant to have self-pressurising systems that only require driving to expel any air pockets?

Today, I drove the car in race mode, and so far, the coolant level has remained stable. The engine bay is dry, and the air conditioning is blowing hot air across all speeds. However, the gurgling sound is still present.

How should I go about resolving this issue?

Additionally, the error code “P16C700: Heater Support Pump Locked” still appears when I scan the vehicle. There seems to be very little information available regarding this code.

Could yourself/someone provide more details on what it pertains to?

 

[Mksleven]

Post in thread 'aux pump issue'
https://golfmk7.com/forums/index.php?threads/aux-pump-issue.374782/post-7955698