Engine Control - Trouble Shooting - No Codes: Other Volvo S80 I

DOES NOT START

Engine Does Not Crank

1. Check starter.
2. Check starter relay.
3. Check engine speed (RPM) sensor
4. Check park/neutral or clutch start switch circuit.
5. Check theft deterrent ECU.

No Initial Combustion

1. Check fuel pump circuit.
2. Check engine speed (RPM) sensor circuit.
3. Check camshaft position sensor circuit.
4. Check power stage circuit.
5. Check MAF sensor circuit.
6. Check ECT sensor circuit.
7. Check fuel pressure.

DIFFICULT TO START

Difficult To Start Normally

1. Check starter signal circuit.
2. Check fuel pump control circuit.
3. Check spark plugs.
4. Check engine speed (RPM) sensor.
5. Check engine compression.
6. Check fuel injector circuit.

POOR DRIVEABILITY

Poor Idling

1. Check coolant temperature sensor and connection.
2. Check air temperature sensor and mass airflow meter.
3. Check coolant temperature sensor.
4. Ensure spark plugs are not fouled.
5. Check ignition and sensor wires for proper connection.
6. Check ignition and coil circuit.
7. Check intake system.

Hesitation/Poor Acceleration

1. Defective mass airflow sensor.
2. Damaged ignition wires.
3. Blocked air cleaner/air intake.
4. Uneven compression.
5. Low fuel pressure.
6. Blocked exhaust system.
7. Faulty sensor signals.
8. Faulty turbocharger (if applicable).
9. Wastegate valve open (if applicable).

Muffler Explosion (Backfire)

1. Ensure timing belt has not jumped.
2. Check for gasoline in oil.
3. Ensure fuel injectors are not leaking.
4. Check ignition and coil circuit.
5. Check engine speed (RPM) sensor.
6. Check throttle switch and connector.
7. Check exhaust system.

Engine Misfire

1. Check fuel injectors.
2. Check ignition and sensor wires for proper connection.
3. Check ignition and coil circuit.
4. Check for gasoline in oil.
5. Check intake and exhaust system.
6. Check for vacuum leaks.

Insufficient Engine Power

1. Check fuel injectors.
2. Ensure fuel pressure is correct.
3. Check mass airflow sensor.
4. Check for restricted exhaust.
5. Check intake and exhaust system.

Poor Fuel Economy

1. Check for leaky fuel injectors.
2. Ensure spark plugs are not fouled.
3. Check for faulty oxygen sensor.
4. Check for poor wire connections and fouled spark plugs.

Excessive HC & NOx

1. Check for gasoline in oil.
2. Check for leaky fuel injectors.
3. Check for faulty oxygen sensor.
4. Check ignition and sensor wires for proper connection.
5. Check engine speed sensor.
6. Check intake system.

Intermittent Simulation

Monitor circuit/component voltage or resistance while using the following procedures to simulate an intermittent fault. If engine is running, check for self-diagnostic codes. Use test results to identify a faulty component or circuit

1. Lightly vibrate component.
2. Heat component.
3. Wiggle or bend wiring harness.
4. Spray component with water mist.
5. Remove vacuum from component.
6. Apply vacuum to component.