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DTC P0170 - Fuel Injection System

  1. Check Exhaust/Intake Air Leak

    Start engine and run at idle. Listen for leaks in exhaust system before three way catalyst. Listen for leaks in intake system after MAF sensor. Repair or replace faulty components as required. If no leaks are detected, go to next step.

  2. Check Front Heated O2 Sensor

    Turn ignition switch to OFF position. Disconnect front heated O2 sensor and ECM harness connectors. Using an ohmmeter check continuity between ECM harness connector terminal No. 46 and front heated O2 sensor harness connector terminal No. 2 (White wire). If no continuity exists, repair open in White wire. If continuity exists, check continuity between ECM harness connector terminal No. 46 (White wire) and ground. If continuity exists, repair shorted White wire. If no continuity exists, go to next step.

  3. Check Fuel Pressure

    Turn ignition to switch to OFF position. Relieve fuel pressure. See the REMOVE/INSTALL/OVERHAUL article. Install fuel pressure gauge. With ignition on, fuel pressure should be about 43 psi (3.0 kg/cm2 ). At idle, fuel pressure should be about 34 psi (2.4 kg/cm2 ). If fuel pressure is not as specified, check for fault in fuel pump and related circuitry. If fuel pressure is okay, inspect MAF sensor. See DTC P0100  - MASS AIR FLOW (MAF) SENSOR and go to next step.

  4. Check Injectors

    Turn ignition switch to ON position. Using a voltmeter, check for battery voltage at ECM terminals No. 102 (Red/Black wire), 104 (Green/Black wire), 107 (Yellow/Black wire) and 109 (Blue/Black wire). If battery voltage does not exist, repair fault in wires as required. If battery voltage exists, go to next step.
  5. Remove injector assembly. Keep all associated fuel lines connected. Disconnect CMP sensor harness connector. Turn ignition switch to ON position. Verify fuel is not dripping from injectors. Replace injectors which are leaking. If no injectors are faulty, go to next step.
  6. Check ECM pins and terminals for damage and check connection of ECM harness connector. Reconnect ECM harness connector and retest.
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