ABS problem with 650 rwhp Supra

[jaebers]

Hello. I have a 97 that received a turbo upgrade plus lots of other items this past winter to get it above 600 rwhp. However, I'm having a pesky ABS problem. Either ABS codes 11 or 13 come on when the brakes are applied and the ABS is not activated. However, when I check continuity on the applicable wires from the solenoid relays to the ABS ECU they are in spec and I can reset the codes by pumping the brakes 10 times in less than 5 seconds. However, as soon as I turn on the car, move a few feet and apply the brakes(without engaging the ABS) the code reappears.

The car has had a serious autocross life so I am replacing both relays. Also, I am beginning to wonder if the front of the ABS actuator/pump is getting too hot due to its vicinity of the turbo, which does not have a thermal blanket...yet (and is on order).

Any info is appreciated.

Thanx!

[pwpanas]

Originally Posted by jaebers

Hello. I have a 97 that received a turbo upgrade plus lots of other items this past winter to get it above 600 rwhp. However, I'm having a pesky ABS problem. Either ABS codes 11 or 13 come on when the brakes are applied and the ABS is not activated. However, when I check continuity on the applicable wires from the solenoid relays to the ABS ECU they are in spec and I can reset the codes by pumping the brakes 10 times in less than 5 seconds. However, as soon as I turn on the car, move a few feet and apply the brakes(without engaging the ABS) the code reappears.

The car has had a serious autocross life so I am replacing both relays. Also, I am beginning to wonder if the front of the ABS actuator/pump is getting too hot due to its vicinity of the turbo, which does not have a thermal blanket...yet (and is on order).

Any info is appreciated.

This may be kind of a shot in the dark, but have you bled the braking system recently? Also, what does your TSRM say about those two codes?

[jaebers]

Originally Posted by pwpanas

This may be kind of a shot in the dark, but have you bled the braking system recently? Also, what does your TSRM say about those two codes?

I haven't bled the brakes lately, but I can give that a try.

DTC 11: ABS Solenoid Relay Circuit: This relay gives power to each ABS Solenoid. After the ignition switch is turned on, if the initial check is ok, the relay goes on.

DTC 13: ABS Motor Relay Circuit: The ABS motor relay supplies power to the ABS pump motor. While the ABS is activated, the ECU switches the motor relay on and operates the ABS pump motor.

I can clear each of these codes with the ignition swich on, the diagnostics jumper in place and pumping the brakes. However, as soon as I turn on the car move a few feet and apply the brakes (without activating the ABS) one of the codes reappear.

[pwpanas]

Originally Posted by jaebers

I haven't bled the brakes lately, but I can give that a try.

DTC 11: ABS Solenoid Relay Circuit: This relay gives power to each ABS Solenoid. After the ignition switch is turned on, if the initial check is ok, the relay goes on.

DTC 13: ABS Motor Relay Circuit: The ABS motor relay supplies power to the ABS pump motor. While the ABS is activated, the ECU switches the motor relay on and operates the ABS pump motor.

I can clear each of these codes with the ignition swich on, the diagnostics jumper in place and pumping the brakes. However, as soon as I turn on the car move a few feet and apply the brakes (without activating the ABS) one of the codes reappear.

Both codes appear to be related to the abs control circuits. If you don't answering one obvious possibility: Is it at all possible that a harness connector has come unplugged, or is not plugged in securely?

Also, your TSRM should have a troubleshooting guide for these two DTC codes. They typically involve checking the voltages/resistances/continuities/etc of harness connections and sensors. Have you already gone these steps for both DTC 11 & DTC 13?

[jaebers]

Originally Posted by pwpanas

Both codes appear to be related to the abs control circuits. If you don't answering one obvious possibility: Is it at all possible that a harness connector has come unplugged, or is not plugged in securely?

Also, your TSRM should have a troubleshooting guide for these two DTC codes. They typically involve checking the voltages/resistances/continuities/etc of harness connections and sensors. Have you already gone these steps for both DTC 11 & DTC 13?

I have been using the TSRM exclusively to help troubleshoot these codes by checking the items you mentioned. I was checking things again last night and I may have found the problem (possible broken wire that occasionally loses continuity when racing, but not during testing---ugh). Since this issue is intermittent, it has been difficult to track.

Thanx for your input.