Sound in Reverse?
Thread Starter
Heel & Toe
Joined: Jan 2025
Posts: 19
Likes: 13
From: Dayton Ohio
Sound in Reverse?
My car which is a 93, ALWAYS makes a weird sounds when backing out of the garage on a cold start (almost as if something is being engaged if that makes any sense). The sound comes in about 10 to 15 feet or so of me in reverse. I never seem to notice it other than when I initially leaving for a drive. Anyone know what this is?
Heel & Toe
Joined: Dec 2024
Posts: 19
Likes: 13
From: Houston, TX
2025 C4 of the Year Finalist - Unmodified
My ‘93 does the same thing but I don’t know if it does the self test under acceleration in reverse. Mine always does it in the same place moving forward after I have executed the precision don’t-scrape-anything manouever very slowly (probably not hitting the threshold to initiate the abs test). I saw a service bulletin on this once but it didn’t say anything about reverse.
Melting Slicks
Joined: May 2019
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From: Mid-Atlantic
2025 C4 of the Year Finalist - Unmodified
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As was mentioned, it's the ABS.
It's doing what it is designed to do.
It's doing what it is designed to do.
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Melting Slicks
Joined: Nov 2016
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From: So Cal
2023 C4 of the Year Finalist - Unmodified
The ABS self-tests at 3 MPH in Forward or Reverse. It is a brief "gurrrrrr". The VSS sensor and wheel speed sensors send pulses regardless of which direction the car is moving. The odometer accrues mileage in reverse as well.
93 also have an electric Secondary Air Injection pump and motor that turns on about 15 seconds after engine start. My 92 remains running for a couple of minutes. Sounds like the cooling fan is running. The noise the OP is hearing is likely the ABS self-test, as you guys figured out.
93 also have an electric Secondary Air Injection pump and motor that turns on about 15 seconds after engine start. My 92 remains running for a couple of minutes. Sounds like the cooling fan is running. The noise the OP is hearing is likely the ABS self-test, as you guys figured out.