PaulNewall
Member
- Joined
- Dec 31, 2023
- Messages
- 10
This relates to another post of mine, but I think it is a general enough question to have its own thread.
I think I may have the main relays in the battery stuck on, and I'd like to be really sure of that before I start taking the battery out of the car.
My car is a leaf 2015, the service manual (now I have the right one for the car) does say something about main relays stuck on. It suggests that shorts in the HV harness or any of the HV coponents (inverter, heater, ac compressor) could give similar DTCs.
The reasons that I think the relays are stuck on are:
1. The first problem was that the leaf would not shut down normally. Stuck relays might be a cause of that.
2. I have a DTC P317A indicating "inverter voltage too high" The manual suggests the inverter may be faulty, but I am thinking the battery voltage being present before start up might also cause this error.
3. When I remove the service plug from the battery, I measure 372V between the service plug's socket contacts. I would expect to measure 0V if either one of the relays were open. With the 12V battery disconnected, the main relays should be open, unless they are stuck.
4. (added 6/1/24) When the battery output HV connectors are unplugged, the voltage across the battery service plug socket is zero.
5. (added 6/1/24) When the battery output HV connectors are unplugged, there's no voltage at the harness side and there's a high resistance at the harness side, this is normal according to the service manual.
6. When I replace the service plug, I get a small but significant arc when it makes contact. I would not expect any current to flow if either one of the main relays were open. I am guessing that the arc is some current charging the capacitor at the inverter input.
Update 23/1/24 I replaced the main relays. They were stuck on as I expected. With the working replacement relays, I measure almost 0V at the service plug socket. So high voltage at the service plug socket, when the battery is in the car, is a good indicator that both main relays are stuck on.
I think I may have the main relays in the battery stuck on, and I'd like to be really sure of that before I start taking the battery out of the car.
My car is a leaf 2015, the service manual (now I have the right one for the car) does say something about main relays stuck on. It suggests that shorts in the HV harness or any of the HV coponents (inverter, heater, ac compressor) could give similar DTCs.
The reasons that I think the relays are stuck on are:
1. The first problem was that the leaf would not shut down normally. Stuck relays might be a cause of that.
2. I have a DTC P317A indicating "inverter voltage too high" The manual suggests the inverter may be faulty, but I am thinking the battery voltage being present before start up might also cause this error.
3. When I remove the service plug from the battery, I measure 372V between the service plug's socket contacts. I would expect to measure 0V if either one of the relays were open. With the 12V battery disconnected, the main relays should be open, unless they are stuck.
4. (added 6/1/24) When the battery output HV connectors are unplugged, the voltage across the battery service plug socket is zero.
5. (added 6/1/24) When the battery output HV connectors are unplugged, there's no voltage at the harness side and there's a high resistance at the harness side, this is normal according to the service manual.
6. When I replace the service plug, I get a small but significant arc when it makes contact. I would not expect any current to flow if either one of the main relays were open. I am guessing that the arc is some current charging the capacitor at the inverter input.
Update 23/1/24 I replaced the main relays. They were stuck on as I expected. With the working replacement relays, I measure almost 0V at the service plug socket. So high voltage at the service plug socket, when the battery is in the car, is a good indicator that both main relays are stuck on.
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