This morning, I tried to start the 2003 Prius and got a 'check engine' light and nothing. The cabin lights were bright so the 12 V looked OK. After three tries, I used the VOM and measured 12.55 V on the battery. But the traction battery level looked unusually low. So I tried again and "voila" it started. Using the ScanGauge, no codes were displayed. So I turned the car off and on three times and cleared the "check engine" light. Then I connected the Auto Enginuity and read out: P1636 - HV ECU Malfunction on the HV ECU to ECM bus. C1213 - HV ECU Communication Circuit Malfunction between HV ECU and Brake ECU P3002 - HV ECU Communication Malfunction on the HV ECU to Battery ECU So it looks like there was an HV ECU problem that 'cleared while testing.' Certainly it makes sense to inspect the HV ECU connectors and re-seat them and clean out any debris. Bob Wilson
Have 2003 Prius well-maintained 130K with sudden warning display: PS, red triangle w/! and car icon. Started once on batt power but I was afraid to drive it. Well, Bob, you've inspired me to try the restart 3x - if it works, I'll drive the car to the mechanic for check up instead of having it towed. Didn't understand much of the other stuff but will tell my mechanic what you've said. Thanks.
You might tell the mechanic that some of your friends remembered the 'sticky throttle plate' problem too. Bob Wilson
