I'm going through the process of troubleshooting an abs light and DTC code C1326 on a Peugeot 308 1.6l 2010 model. The DTC message I am getting from the scanner reads

C1326 - Status: Test is inhibited by other DTC, Validated and stored in non-volatile memory.

What does 'Test is inhibited by other DTC' mean?

  • Welcome to Motor Vehicle Maintenance & Repair! Commented May 19, 2023 at 16:09

1 Answer 1


As your vehicle operates, the Electronic Control Unit (ECU) and other control modules (ABS) are constantly running tests to ensure various systems are operating correctly. These tests are run at certain intervals depending on the system. Some tests are run every time the engine reaches operating temperature, every X number of times the engine reaches operating temperature, when the system completes a loop, every few milliseconds, etc.

When a test fails, it sets a Diagnostic Trouble Code (DTC). The control modules will continue to run the same tests at regular intervals until they confirm there is a problem.

The C1326 code refers to LH rear wheel speed sensor: operating field / performance.

What you are seeing is a status bit for the C1326 DTC. The status bit offers additional information about the DTC.

In particular, this status bit tells you that another DTC is prohibiting a test relating to C1326 LH rear wheel speed sensor: operating field / performance from completing.

It is standard practice in automotive diagnostics to deal with DTC in the order they are received. One issue can lead to multiple system failures and thus multiple DTCs. Start by diagnosing the first DTC found in the system memory. Even if they seem unrelated.

It's likely that your driver-side rear wheel speed sensor is bad. Other possible issues include:

  1. Bad driver's side rear wheel bearing.
  2. Faulty wiring or wiring connection.
  3. Bad ECU or ABS Module.
  4. Out of tolerance gap between the ABS tone ring and the wheel speed sensor.
  • Thanks, the first DTC I get is a P2196 heated oxygen sensor stuck rich. Can I ask where you found the information relating to the C1326? Just to check, I'm in the UK so LH side would be my passenger side here?
    – jamie1989
    Commented May 20, 2023 at 7:18
  • There are various sources relating to DTC codes online. Unfortunately, there is nothing I can find online related to this manufacturer-specific code. I was able to get the DTC information from speaking with a Peugeot dealer in Mexico. The sensor is on the left rear side of the vehicle while sitting in the driver's seat. So, yes, you are correct. :)
    – Kevin A
    Commented May 20, 2023 at 14:01

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