# VE Commodore V8 Alternator light, no charge p0621
08/10/2014 | Author: admin | No comments | Categories: blog • Diagnostics
# Vehicle
### Holden Commodore VE SS V8
# Symptom:
The alternator light comes on on dash board that warns you that the alternator is not charging, The late model vehicles have ECU controlled, charging circuits and no longer just use the battery for sensing, the alternators are pulse width controlled by the ECU for charge rates from the alternator. When the alternator lights comes on you now have to ask your self is the battery not being charged due to a faulty alternator or is the Engine ECU not sending a signal, or worse both,
# Testing
The Alternator light was on in the instrument cluster, how ever they still will hold a fault code, so it is always best to check the fault code number to get a clearer picture on what the fault is.
Once the fault codes where checked we found
- P0621 – Generator lamp L control Circuit.
# Repairs
P0621 fault code, scope to test circuit integrity,
Replacement Bosch alternator
# Summary
After spending a few hours on testing and preparation of learning the way GM had decided to build this system and work out that they also have a battery current sensor located in the boot to measure current draw over a time period, we where confident that the testing method we had used was the right way before just installing a new alternator, rather than fit and find out way later.
## Images
Book in
Similar issue on your vehicle? Call the workshop and we will advise what to expect.