Toyota Prado: 1GR-FE Secondary Air Injection Pump and Check Valve Failure

The secondary air injection (SAI) system on the 1GR-FE 4.0L V6 petrol engine pumps fresh air into the exhaust ports during cold start to accelerate catalytic converter light-off and reduce hydrocarbon emissions. The system's rubber-diaphragm check valves crack after heat cycling, allowing exhaust gas backflow to reach the electric pump motor; the hot, acidic exhaust gas destroys the motor windings and seizes the impeller, typically between 80,000 and 150,000 km. Failed check valves alone cause intermittent faults, but once the pump motor seizes the repair cost escalates significantly.

• Check engine light on cold start that may clear after the engine warms up
• Audible absence of the secondary air pump sound during the first 60 seconds of a cold start
• Failed warrant of fitness emissions test due to elevated cold-start hydrocarbons
• DTC codes P0410, P0411, or P0418 stored in the ECM

With the engine cold, start it and listen for the pump running for approximately 60 seconds from a low position near the right inner guard — a seized pump produces silence or a single click from the relay. Physically inspect the rubber check valves on both exhaust manifold banks for cracks or heat distortion. If a workshop inspection is possible: Connect a scan tool and check for codes P0410 (SAI system malfunction), P0411 (incorrect SAI flow), and P0418 (SAI pump relay circuit).

Parts involved: High-pressure fuel pump.

$900 to $2,800 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

• “Has the secondary air injection pump or check valves ever been replaced?”
• “Does the check engine light come on during cold starts and clear after the engine warms up?”
• “Can you demonstrate a cold start so the SAI pump can be heard running?”

The failure described above is documented in published sources — owner forums, technical service bulletins, recall notices and workshop write-ups — held in our fault database. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them, and it is a starting point for an inspection rather than a manufacturer statement.