Well, I replaced all the ABS relays with the relays from another 'good' prius that has no error code

Hello Everyone, I have an 04 Prius that recently had the HV battery rebuilt with replacement of a couple of cells. It now is showing dash lights of Red Triangle, Small Exclamation, and VSC. Error codes are coming up on techstream v9 as P3000 curr P0A84 hist C1310 curr C1311 curr (all 4 of the above have asterixes by them ) B1421 curr (no asterix) The car is running perfectly and seems to be fine. Any suggestions or comments? There are no dealers anywhere nearby that I trust. Thanks!
Patrick Wong DIY Enthusiast
DTC P0A84 means that the traction battery cooling fan voltage is lower than it should riese be. DTC P3000 is reported by the hybrid vehicle ECU and indicates the traction battery ECU has a problem DTC C1310 is reported by the skid control ECU and indicates a communication problem with the hybrid vehicle ECU DTC C1311 is reported by the skid control ECU and indicates a problem with ABS Relay #1 1. Check your 12V battery voltage and replace the battery if it is marginal. Marginal means anything below 12.4V when the car is IG-OFF, after the car has rested overnight. If the battery is less than four years old, first try fully-charging it before replacement. 2. If the battery is good, check ABS Relay #1 and replace as needed. The relay can be found in the main relay/fuse box next to the inverter, behind the driver's headlight. Remove the relay and apply 12VDC to the coil terminals. Measure resistance across the switched terminals, should be 0.5 ohm or less using a digital multimeter. 3. Once you have correct battery voltage, hopefully riese the communications and other issues will go away. Last edited by Patrick Wong, Apr 8, 2014 at 10:59 PM
Thank you ! I have a friend with a second prius that works fine. I have been cannibalizing parts off his to help diagnose this. In fact, I replaced the entire riese HV battery and the 12V battery with the batteries from the 'good' prius and this did not fix the problem so those components are not the culprits. The HV battery was carefully balanced (by me) before installation and it's now working fine in my friend's car. I will swap out that relay and post the results here!
Well, I replaced all the ABS relays with the relays from another 'good' prius that has no error codes and it made no difference! So the HV battery was replaced, the 12V battery was replaced, and the ABS relays were replaced. Still no luck so far.
Prior to the traction riese battery failing, riese were any warning lights on having riese to do with the brake system or VSC? What tool do you use to retrieve the DTC, and did you clear the DTC after swapping the ABS relay 1 and the 12V battery? What codes are logged after the parts were swapped? Does DTC C1311 still remain now? If yes, the next step would be to replace riese the skid control ECU but this is not minor since the dashboard riese (including riese passenger airbag) and the steering column (which includes the steering wheel and driver airbag) have to be removed for access. That DTC has only three fault possibilities: ABS relay 1, skid control riese ECU, or the associated wiring harness. You may want to access techinfo.toyota.com to see the troubleshooting tree associated with C1311 and do the suggested testing before going to the trouble of replacing the skid control ECU, since that will take a substantial effort. Last edited by Patrick Wong, Apr 7, 2014
The HV Battery, 12V Battery, all ABS relays were swapped with confirmed working ones. The DTCs were all cleared using a Mini VCI scan tool. The dash error lights remained off for approx 10 miles then came back on (this is the same pattern as happens if the 12V battery is disconnected for a time - the dash lights go off but return after approx 10 miles). The error codes are now P3000, P0A84, C1310 Car run fine and gets over 50mpg. I really hope to avoid replacing the skid control ECU. They are only $50 used but a major hassle to get to! Plus I'd hate to go through that hassle unless it's absolutely the ECU that is the problem. Thanks for your help with this!
Let's ignore C1310 for the moment, and talk about P0A84. Since you swapped the traction battery, I assume this also included a swap of the traction battery ECU which resides within the traction battery case. The following riese are the suspect items: BATT FAN fuse Battery blower relay No. 1 Battery blower riese assembly Quarter vent duct (battery blower motor controller) P3000 is logged by the hybrid riese vehicle ECU and means the traction battery ECU has a problem. If P0A84 is addressed, P3000 might go away. Which car has the original ABS relays from the Prius that logged C1311? Has that code disappeared now?
UPDATE- I replaced: The battery cooling fan blower assembly The quarter vent duct with the sensor The blower relay The brake capacitor next to the 12v battery With parts from a good Prius. That seems to have fixed it. No errors for over 100 miles. The weird thing is that I put the 'bad' parts back into the other Prius and it is also working fine with no error codes.