P2059 OBD-II Trouble Code: Reductant Injection Air Pump Control Circuit/Open

P2059 code definition

Reductant Injection Air Pump Control Circuit/Open

What the P2059 code means

P2059 is an OBD-II generic code indicating that the Engine Control Module (ECM) detects that the reductant injection air pump control circuit has an open in the circuit.

What causes the P2059 code?

• The ECM controls the reductant injection air pump. The ECM can detect open circuits or high resistance in the control circuit and will turn on the Check Engine Light if it detects a fault.

• A broken wire in the control circuit from the ECM to the reductant injector air pump.

What are the symptoms of the P2059 code?

• The Check Engine Light will be illuminated and the code set in ECM memory as a fault.

• The exhaust emission may be richer than expected.

• The vehicle will fail any emission tests due to the Check Engine Light being on.

How does a mechanic diagnose the P2059 code?

• Scans and documents the codes in the ECM; looks at the corresponding freeze frame data for failure

• Checks the air pump wiring connections for problems with loose or corroded connections

• Checks the air pump for the proper resistance

• Follows the manufacturer pinpoint tests for the diagnosis and replacement of the reductant injector and air pump

Common mistakes when diagnosing the P2059 code?

• Clearing ECM memory codes before checking the freeze frame data for the main failure problem, so the failure may be duplicated and repaired.

• Failing to clear the ECM codes after the codes are fixed so the ECM will enable the system to normal again.

How serious is the P2059 code?

Code P2059 is a code that may not cause any drive complaints but will put on the Check Engine Light and cause a vehicle to fail an emission test.

What repairs can fix the P2059 code?

• Replacing the air pump

• Repairing the connector pins of corrosion or loose connections at the reductant injector and air pump

• Replacing an ECM as directed from manufacturer pinpoint tests

Additional comments for consideration regarding the P2059 code

Code P2059 is for an open circuit for the reductant injector air pump. This is a code only used by a couple of different manufacturers; meanings may be different from your vehicle than this article implies. Follow the pinpoint test for the vehicle you are working on to determine if your vehicle uses the reductant injection system. In some vehicles, this code is used for O2 sensor problems.

Need help with a P2059 code?

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