Revs Rising to 1000rpm at Idle

[Golf-Fiend]

Dear all.

 

I noticed over the last few days that sometimes when sat in traffic my revs suddenly rise to 1000rpm and stay there. No other issues.

 

Car is 2.0TDi BKD 2004 so has no DPF.

 

Ran a code check using a hand held OBD tool. and it came back with :

 

• 18051 Please check DTC Memory of Electric Load Controller: P1643
• 02386 Rain/Light Recognition Sensor Function restriction due to Over Voltage
• 01598 Drive Battery Voltage (no fault code)

 

Looking up these errors brought up these two links:

 

https://forums.ross-tech.com/showthread.php?14822-Audi-A3-TDI-with-P1643

 

http://www.vwaudiforum.co.uk/forum/showthread.php/123946-Error-code-18051-p1643/page2

 

Some say it is an alternator fault and others have replaced the battery. I'm thinking my battery is around 5-6 years old. It's a Bosch battery but now out of warranty.

 

Any ideas how to troubleshoot this? Check Alternator Output and Battery condition.

 

Many thanks

 

 

 

[langers2k]

I'd start by getting the battery tested

[Golf-Fiend]

Cleared fault codes on Saturday. Rescanned again today and only fault was " 01598 Drive Battery Voltage (no fault code) "

 

After messing about with my Multimeter I have found the following:

 

12.72V at rest engine off

14.28V at 2000rpm

14.08V at 850rpm idle speed

 

I'll test battery again in the morning after it has been sitting for 12 hours and see what the results are.

[Quiksilver_TR]

Give this a read.

 

 

I solved this issue on my CR engine.

Post might save you time and money

[Golf-Fiend]

10 hours ago, Quiksilver_TR said:

Give this a read.

 

 

I solved this issue on my CR engine.

Post might save you time and money

 

Many thanks for sharing this. Very useful. I will check my Earthing points over Easter. Give them a good clean and cover them with grease.

 

Kind regards

 

Nic

[Golf-Fiend]

Well, Battery Voltage this morning was 12.60V after standing all night.......

[Golf-Fiend]

On 15/04/2019 at 22:37, Quiksilver_TR said:

Give this a read.

 

 

I solved this issue on my CR engine.

Post might save you time and money

 

 

Well........... I removed battery/airbox/front lights/scuttle cover etc etc and found and cleaned as many Earthing points as I could find. There are quite a number! None of them look particularly corroded or dirty. Gave them all a good rub with emery cloth and re-clamped good and tight.

 

The jury is still out on this one - however since doing this the problem has not yet recurred. I'm loath to say that it is cured as I cannot believe that this was the cause. I will continue to monitor and report back after a month.

 

Thanks for the heads up on this Quicksilver_TR. 

[Jevpls]

Sometimes revs might rise to 1k rpm just because of the weather. Really. If it's too hot outside and AC is on - it needs power for that and revs rise. If it's too cold then revs also rise.

 

[Golf-Fiend]

11 hours ago, Jevpls said:

Sometimes revs might rise to 1k rpm just because of the weather. Really. If it's too hot outside and AC is on - it needs power for that and revs rise. If it's too cold then revs also rise.

 

 

Thanks Jevpls.. However very unlikely to be that in my case. I've had the car for 11 years and it has never done this before in any weather.

 

Anyway - so far so good........ Still waiting for the issue to return...

[makky1984]

i'm owning 2011 2.0 TDI DSG. i'm facing this 1K rpm issue while stop in traffic (morning after starting if AC gets ON, rpm raise to 1K). i asked Skoda service person they told, this condition happens during battery charging. i'm not convinced with their answer.

- i have change 70amps battery last month. but the problem is still there.

can anyone suggest me a solution for this problem.

Note: in my town temperature will be 35-40 degree.

[langers2k]

1 minute ago, makky1984 said:

 i'm facing this 1K rpm issue while stop in traffic (morning after starting if AC gets ON, rpm raise to 1K).

 

Air conditioning requires power from the engine, mechanically to drive the compressor and electrically for the fan.

 

If there are no other issues with your car, it'll be the ECU sensing the extra load and raising the RPM to compensate.

[makky1984]

Thanks for the feedback langer2K.

 

i'm not getting any error code related to engine, except seat lumber support circuit intermittent. 

do you nave any suggestion to solve this ECU related problem?

And recently i have changed Flywheel and Clutch unit for my car at skoda authorized service center.

Edited 2 May, 2019 by makky1984

[Golf-Fiend]

3 hours ago, makky1984 said:

Thanks for the feedback langer2K.

 

i'm not getting any error code related to engine, except seat lumber support circuit intermittent. 

do you nave any suggestion to solve this ECU related problem?

And recently i have changed Flywheel and Clutch unit for my car at skoda authorized service center.

 

Try cleaning up all the Earthing points in the engine bay. you need to remove the Battery cover/housing and the Airfilter box for this. There must be around 10 or 11 points to clean with emery paper and re-clamp. Also one in the scuttle area for the ECU. You can just reach this by lifting the LHS scuttle cover. There is one on the RHS but you need to remove the headlight to get to it.  If you have the tools, the time and the ability then it is free and you have nothing to lose.

 

Hope this helps? It seems to have helped mine.

 

Just to add my revs never rose with AC on or off in hot or cold weather. They were always a very steady 850rpm until I had issues.

[Quiksilver_TR]

If the cars have stop-start tech there is an ECU under the front seat which manages the battery loading/charging/voltage etc which can have issues and gives the Rev rising issue too.

[Jevpls]

3 hours ago, Golf-Fiend said:

Just to add my revs never rose with AC on or off in hot or cold weather. They were always a very steady 850rpm until I had issues.

 

Strange, I've seen such behavior for years even if everything else was fine.

I have 2.0 TDI CR engine, though. Your's is PD.

 

 

[makky1984]

I did clean all the Earthing points except ECU point (not able to locate that point), but the rpm issue is still there in traffic condition. 

 

Engine is 2.0 CR with DSG 

Model 2011.

[Golf-Fiend]

Sorry to hear you are still having problems. Mine is a PD engine and yours a CR so what worked for me maybe not for you

 

The ECU and its Earth point are under the plastic scuttle (where the wipers are) almost directly behind the battery area

[makky1984]

Thanks friends for your suggestions. Adding to the 1K idling issue, last week coolant reservoir low alarm raised. I topped up with water and regularly monitoring the level of coolant. suggest me whether both problems are related to each.

[Golf-Fiend]

Update: So far the issue has not returned. Still not convinced as to how cleaning the earth points helped as none were that corroded to be a concern. Possibly the extended battery disconnection whilst doing this has reset the ECU?

[makky1984]

Update: I took my car to Skoda Service, they checked the cooling system with 2 bar pressure and they found a tiny small hole in the Radiator. they suggested to replace with a new one and i did that with fresh coolant. Now the car is running fine and i have not noticed no 1000 RPM increase at idling (except AC on for the first time). Hope the problem is rectified.