DTC P0170 (Fuel) - Fuel Trim Malfunction
- Check for the following items in exhaust system:
- Looseness of installation components
- Damage to parts (cracks, holes, etc.)
- Looseness or opening of parts between front and rear O2S
Replace or repair defective parts. If no defects, go to next step.
- Check for the following items in air intake system:
- Looseness of installation components
- Damage to parts (cracks, holes, etc.)
- Disconnection of hose on air intake system
Replace or repair defective parts. If no defects, go to next step.
- Remove fuel pump access cover located a right rear of trunk (sedan) or luggage compartment floor (wagon). Disconnect connector from fuel tank. Start engine and run until it stalls. After engine stalls, crank for 5-7 seconds to ensure reduced fuel pressure. Turn ignition to OFF. Connect fuel tank connector. Disconnect fuel delivery hose from fuel filter and connect a fuel pressure gauge between filter and delivery hose. Start engine and idle with transmission in park or neutral. Measure fuel pressure with pressure regulator hose disconnected from intake manifold. If fuel pressure is 33-40 psi (2.3-2.8 kg/cm2
), go to next step. If fuel pressure is too high, repair for clogged fuel return line or bent hose. If fuel pressure is too low, repair for improper fuel pump discharge or clogged fuel supply line. Measure fuel pressure with pressure regulator vacuum hose connected. If pressure is 23-30 psi (1.6-2.1 kg/cm2
), go to step 4). If fuel pressure is too high, check for faulty pressure regulator, clogged fuel return line or bent hose. If fuel pressure is too low, check for faulty pressure regulator, improper fuel pump discharge or clogged fuel supply line.WARNING: Release fuel pressure before removing fuel pressure test gauge.NOTE: After installing fuel pressure test gauge, if fuel pressure does not increase, squeeze fuel return hose 2-3 times and recheck fuel pressure. If out of specification with vacuum hose attached, check pressure regulator and vacuum hose and replace as necessary.
- Turn ignition to OFF. Connect SSM or OBD-II scan tool to data link connector. Start engine and allow to warm completely. On SSM, select function mode F05 to read coolant temperature in °F or F06 to read coolant temperature in °C. If temperature indicated is more than 140°F (60°C), go to next step. If temperature reading is not okay, replace coolant temperature sensor (CTS).
- On SSM, select function mode F47 to show mass air flow. If the mass air flow is not within the specifications shown in the MASS AIR FLOW SENSOR VALUES table, replace MAF. If mass air flow is within specification, substitute a known, good ECM and retest.
MASS AIR FLOW SENSOR VALUES
| Engine Speed | Specified Value (g/sec) |
|---|---|
| Idling | 1.9-3.6 |
| 2500 RPM | 7.0-14.8 |