Diagnosis & Repair
WARNING: This page is about a different car, the 2002 Toyota Prius. However, it is still accessible from the selected car via links, so may be relevant.
- Check vacuum hose and line between HCAC VSV and the actuator for restrictions or damage. HCAC VSV is located on bracket bolted to timing chain end of engine and uses a Brown 2-pin electrical connector with Black and Black/White wires. See Fig 1. Actuator is located at front of three-way catalytic converter on exhaust pipe. See Fig 2. If vacuum hose and line are okay, go to next step. If vacuum hose or line are restricted or damaged, repair or replace components as necessary.
- Start engine and warm engine to normal operating temperature. Shut engine off. If Toyota hand-held tester is available, go to next step. If Toyota hand-held tester is not available, go to step 4.
- Connect hand-held tester to Data Link Connector (DLC) No. 3 at driver's side of instrument panel. See Figure. Start engine. Turn hand-held tester on. Select proper mode on hand-held tester to operate HCAC VSV. Go to step 5.
- Disconnect electrical connector at HCAC VSV. Apply battery voltage and ground to electrical terminals on HCAC VSV to operate HCAC VSV. See Fig 3. Start engine. Go to next step.
- With engine idling and HCAC VSV operating, check that rod on actuator is pulled inward and that by-pass valve moves. If rod on actuator is not pulled inward and by-pass valve does not move, shut engine off and remove jumper wire (if used). Go to next step. If rod on actuator is pulled inward and by-pass valve moves, HCAC system is operating properly. Shut engine off. Reinstall electrical connector at HCAC VSV if removed and disconnect hand-held tester (if used).
- Check for dirt on shaft of by-pass valve which would prevent by-pass valve operation. If no dirt exists, go to next step. If dirt exists, clean as necessary and recheck operation of by-pass valve.
- Check for bent rod on actuator and for bent actuator mounting bracket. If rod and mounting bracket are okay, go to next step. If rod or mounting bracket are bent, repair or replace components as necessary.
- Remove front exhaust pipe. Remove actuator from front exhaust pipe. Using vacuum pump, apply 9.83 in. Hg of vacuum to actuator while checking to see if rod on actuator is pulled inward. If rod is pulled inward, actuator is operating properly. Go to next step. If rod is not pulled inward, replace actuator.
- Check that by-pass valve will rotate in front exhaust pipe. If by-pass valve will not rotate, replace front exhaust pipe. If by-pass valve will rotate, it is assumed that front exhaust pipe is defective. Repair or replace front exhaust pipe as necessary. Reinstall actuator and front exhaust pipe.