Diesel Data: Automotive Repair

Volume Does Not Increase With Speed

Volume does not increase with speed

1. Verify the SVC mode setting in the navigation or audio unit sound set-up.

Is the SVC set to off?

YES - Change the setting to "Mid" and retest.

NO - Go to step 2.

2. Remove the audio unit, and disconnect the audio unit connector C (40 P).




3. Drive the vehicle, and have an assistant measure voltage at audio unit connector C (40 P) terminal No. 26.

Is there 0 - 6.5 V.

YES - Replace the audio unit.

NO - Repair open or shorts in the wire between the audio unit connector C (40P) No. 26 terminal and the ECM/PCM connector E (44P) No. 11 terminal. If no opens or shorts are found, substitute a known-good ECM/PCM and recheck. If the symptom/indication goes away, replace the original ECM/PCM.