The owner of a 2014 Volvo S60 came into the repair shop concerned that the parking assist wasn't working and there was a park assist fault message on the instrument cluster.
Case details
When the technician connected a scanner, he found numerous diagnostic trouble codes (DTCs) in the PAM (park assist module):
- B1B4414- Communication with the parking sensor, external, right rear
- B1B4614- Communication with the parking sensor, inner, right rear
- B1B4814- Communication with the parking sesnor, external, left rear
- B1B5014- Communication with the parking sensor, inner, left rear
- B1B5811- PAM checks the voltage supply to the rear parking sensors
- B1B3614- Communication with the parking sensor, external, right front
- B1B3814- Communication with the parking sensor, inner, right front
- B1B4014- Communication with the parking sensor, external, left front
- B1B4214- Communication with the parking sensor, inner, left front
- B1B5711- PAM checks the voltage supply to the front parking sensors
Given the number of DTCs, the technician called ALLDATA Tech-Assist for some time-saving diagnostic advice.
The Tech-Assist consultant recommended checking for corrosion in any of the parking assist sensors. NOTE: One bad sensor might short the reference voltage for the others, which could trigger all the DTCs and cause the system malfunction.
If all the sensors checked out well, the next step would be to inspect the wiring and connectors for the PAM. If all those were okay, then the PAM would likely be the problem.
The technician inspected the sensors and connectors as suggested, and they all were good.
He opened the PAM and found some burned components inside.
Confirmed repair
The technician replaced the PAM and cleared all the DTCs. After that, the parking assist system worked normally. Problem solved!
