This week we had a visit from a 2016 Chevrolet Volt that had a charging problem.

To find out where we’re heading, a quick look at the fault codes will help us find a good diagnostic chart: P1EC1Battery Energy Control Module High Voltage Energy Management Communication Bus Enable Circuit Low Voltage.

In the description of the problem circuit, we are told that the HybridPowertrain Control Module 2 (HPCM2) supplies this circuit to wake up the Battery Energy Control Module. (BECM) and communication begins. If you expect to see a power source and there isn’t one, this fault code is recorded.

Let’s start the diagnosis. For the first stage, we are asked to ensure that there is no code U185B. This is not the case.

The next step is to disconnect the X357 connector at the front of the high-voltage battery and check that by connecting a test lightbetween terminal number 5 and earth, it lights up. In our case, it doesn’t light up.

Validate before replacing

If this is the case, the next steps require us to check whether the circuit is earthed, and whether it is open between the HPCM2 and the BECM. All correct.

So the recommendation is to replace the HPCM2.

Once again, the replacement of a module is not always pleasant to announce to a customer without knowing whether this is the end of the repair.

In the first test, we are asked to take a control lamp. We all agree, a pilot light needs 12V to light up. So I decided to do the work of the HPCM2 and inject 12V into this circuit with the on key. .

The code disappears, and the vehicle recharges without a hitch. Bingo! We are 200% certain that the repair we will recommend will work.

HPCM2 replaced, programming done, the little Volt 2016 was back on the road!