Help! Electrical Issues (CANBUS?) - Multiple Warning Lights

Reply Subscribe

Thread Tools

Search this Thread

Sep 17, 2023 | 01:58 AM

#21

Gillsy

Thread Starter

Junior Member

Joined: Aug 2023

Posts: 16

Likes: 20

From: Cheltenham, UK

Quote:

Originally Posted by scottjh9

your reading is ok. 60 or so ohms means a possible bad resistor or module with everything plugged in. On my car the resistors are in the abs module and the ecm. Yours might be differen. Unplug a module and then check the two pins again. When you get 60 ohms or so you have found one. It is best to disconnect the neg terminal at the battery when disconnecting or connecting a module. It will not affect your ohms test. The module should not be awake in any way when messing with plugging or unplugging it. I just went through a similar canbus issue. Google up canbus diagnostics and you will find some very helpful info on troubleshooting

Are you sure? I thought that the two 120 Ohm terminating resistors in parallel should work out at 60 Ohms (indicating a good reading). Testing from the data link connector if I see 120 Ohms this would indicate a fault?
I have corrected a mistake, the reading taken was around 105 Ohms.

Sep 19, 2023 | 01:18 PM

#22

scottjh9

Veteran Member

Joined: May 2018

Posts: 2,137

Likes: 759

From: california

you are right the 60 ohms is good between the pins 6 and 14....i got backwards.....had to read thru the article again.....sorry.....if you are getting 105 ohms with everything plugged in then you do have a problem somewhere...there are a few other multimeter tests you can do at the dlc link also....the instrument cluster is the gateway for all network comms except d2b i believe....you can still do the unplug one module and check ohms to narrow things down a bit

Mar 2, 2024 | 09:51 AM

#23

Gillsy

Thread Starter

Junior Member

Joined: Aug 2023

Posts: 16

Likes: 20

From: Cheltenham, UK

Fixed?! (Instrument cluster at fault)

Just got the car back after a lengthy stint at the garage.

The fault is (hopefully) fixed. I had suspected the instrument cluster as a likely suspect as I was experiencing high resistance on the can circuit. The instrument cluster was sent away for inspection/repair, and they found a few dry solder joints on the PCB. The brake switch was also changed to rule this out.

Time will tell if everything is sorted.

Mar 2, 2024 | 10:15 AM

#24

scottjh9

Veteran Member

Joined: May 2018

Posts: 2,137

Likes: 759

From: california

Excellent

Mar 6, 2024 | 11:35 AM

#25

Prettykitty

Member

Joined: Apr 2023

Posts: 44

Likes: 18

From: Ohio

Great job troubleshooting and I/we really appreciate the documentation you provided! Hope this is licked for good!

Mar 11, 2024 | 08:56 PM

#26

scottjh9

Veteran Member

Joined: May 2018

Posts: 2,137

Likes: 759

From: california

If you get an a/b correlation brake switch fault it is an easy adjustment. Real common when one of the switches is replaced

Apr 26, 2024 | 01:36 PM

#27

Gillsy

Thread Starter

Junior Member

Joined: Aug 2023

Posts: 16

Likes: 20

From: Cheltenham, UK

Another update. Dropped the car off at another garage this week. Within 2 days they claim to have diagnosed an fixed the problem - a loose pin into the instrument cluster. Fingers crossed this time.