DTC4-Grounded Antilock Valve Reset Switch


My truck is a 1992 c1500 (120k) with RWAL. The brake light in the instrument cluster came on about three weeks ago. I notice that if I set the emergency brake the light would get brighter. After ignoring the light for two weeks, the light began to flash a code at me (one long flash, then three short flashes). From what I can find, this error code is DTC4-Grounded Antilock Valve Reset Switch.

My problem is that my Chiltons book does not explain where this switch is and my local Auto Zone and my local Chevy parts dealer do not know what this part is.

Does anyone know where it is, how I can test it and what I need to tell the dealer to get the right part?




Are you sure you are reading the code right? Could it be code 13?


I thought the process is to count the number of short flashes starting from the long flash. Include the long flash as a count.


Your problem may be that the solenoid valve is in the ABS unit. So far I have not found any repair information on ABS units – probably because of the liability problem. Usually the only repairs that can be done is to change wheel sensors, repair wiring, and check for appropriate power supply. Anything inside the ABS unit is fixed by replacing the entire thing.

I think there are companies which rebuild ABS units but I don’t know if you have to send your unit back or if they can deliver a unit off the shelf.

Good Luck


It’s been awhile since I’ve had to work on a RWAL but I thought the long flash was the first number then the short flashes were the second number. I triied to find some information on reading the codes but I wasn’t able to find any.

Can anyone out there help?