Treb Reader
12/20/11 10:09 p.m.

I have a 98 A4 -- one of the early 30v cars.

About 145,000 miles.

CEL came on tonight.

Checked the code: 18010 - Power Supply Terminal 30: Voltage too Low P1602 - 35-10 - - - Intermittent

Volt meter in the instrument cluster shows a solid, constant 14v when running -- I've never seen the needle waver.

According to my notes, the same thing showed up about 13 months ago.

Other than "14-Year-Old VW in Quirky Electrics Shock!", any thoughts or suggestions?

Thanks Matt

Ian F
Ian F SuperDork
12/21/11 6:58 a.m.

Check for corrosion on the terminals, reset and see if it comes back.

How old is the battery? Modern cars can get weird when the battery gets old.

Treb Reader
12/21/11 5:39 p.m.

I'll brush the terminals this weekend... battery was in the car when we bought it, 2+ years ago. I'll have to check the files that came with the car -- awesome service records.

Thanks Matt

audifan Reader
12/22/11 7:55 a.m.

Here ya go P1602 power supply low voltage t-30
Corrective action - check power supply to ECM

Do you have access to Stabilant 22a ? if so remove all ECU electrical connectors and apply 22a to all pins then clear codes and recheck.

If the code comes back you are going to need to look @ the system with a Vag-Com to and look at some very specific values which will either point you towards a wiring repair or not

Good luck

Treb Reader
12/22/11 3:18 p.m.

CEL came back today in a similar situation -- long cruise on the highway, then exit into stop-and-go traffic; fall to idle.

Audifan: I do not have "Stabilant 22a." Is this electrical grease, or something else?

What values need checking in Vag-com?

Thanks Matt

iceracer SuperDork
12/23/11 9:46 a.m.

Check the grounds.

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