2006 V70R CEM issues after heater core replacement

Geevs · Post by **Geevs** » 01 Jun 2026, 16:36

A Volvo shop replaced my heater core and now the CEM is acting up. CEM never had an issue prior to this. CEM would throw random codes within 5-10 minutes of engine running.

Coolant spill suspected. According to the mech, connector to CEM was checked and it was dry. Same with the SUM. Brake pedal sensor was a bit wet.

He still cleaned up the CEM, SUM and brake pedal sensor connectors with compressed air and electrical cleaner for good measure.

CEM still throwing random codes but after a longer period - like after 20 minutes. Seems like it's still wet somewhere. Any suggestions where to look?

Apologies for the cross-post with another forum.Urgently need advice so I can get the car out of that shop. Thanks!

Post by **vtl** » 03 Jun 2026, 08:47

List of codes your CEM is throwing please?

Vova585 · Post by **Vova585** » 03 Jun 2026, 11:40

I have hard time linking heater core to CEM especially for "volvo shop" shop performed job. They most likely billed for hours listed for dash removal method and instead slightly bent tge lines and replaced the heater core. Way faster abd probably way safer when dealing with 20 year old connectors and plastic.
Agree with vtl. Lets see the codes.