Brake warning light flashing

STOCK0823

MEMBER
1990 GMC VAN
5.7L
V8
2WD
AUTOMATIC
77,000 MILES

Brake light in dash flashes a code 6, which according to chart, is a bad speed sensor. My van is a g3500, 350 v8, 400 turbo transmission. I do not know where speed sensor is located. Can you help?

Sunday, October 21st, 2018 AT 6:33 PM

2 Replies

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

Hi and thanks for using 2CarPros. Com.

The code indicates an erratic signal in the speed signal. It could be a bad sensor, partially disconnected sensor, or damaged wiring/connector/corrosion. I attached two pictures for you. The first one indicates the location of the sensor (left side of transmission). The second is a diagnostic flow chart.

Let me know if you have other questions or need additional information. Also, ignore picture 2. For some reason I cannot delete it.

Take care,
Joe

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