Volvo

Electronic Viscous Fan: The Electronic Fan Drive contains a solenoid that controls the flow of fluid between reservoirs in the fan drive housing and cover. The Engine Control Module (ECM) provides a (PWM) Pulse Width Modulation signal to the solenoid and controls solenoid operation to optimize fan speed, based on coolant temperature, intake air temperature and A/C load.

Conditions for diagnostic trouble code (DTC):
1) The fan solenoid valve is activated because the control wire is shorted to ground
2) Short circuit to ground on A14.EB:49

Observable symptoms
1) Engine fan permanently disengaged
2) High engine coolant temperature (ECT)

Probable cause
1) Solenoid valve, engine fan
2) Wiring harness
3) Connector
4) Engine control module (ECM)

Electronic Viscous Fan: The Electronic Fan Drive contains a solenoid that controls the flow of fluid between reservoirs in the fan drive housing and cover. The Engine Control Module (ECM) provides a (PWM) Pulse Width Modulation signal to the solenoid and controls solenoid operation to optimize fan speed, based on coolant temperature, intake air temperature and A/C load.

Conditions for diagnostic trouble code (DTC):
1) The voltage at pin A14:A14.EB:49 is below normal value

Observable symptoms
1) Engine fan constantly engaged
2) High fuel consumption

Probable cause
1) Solenoid valve, engine fan
2) Open circuit on signal wire
3) Open circuit in the voltage supply, Solenoid valve(s)
4) Connector
5) Fuse

Fuel Injector operation is controlled by the Engine Control Module (ECM). The ECM provides a common supply voltage to injectors 1,2,3 (Bank 1) and there are individual output transistor drivers inside the ECM to control each individual injector?s ground circuits. There are two solenoid circuits within the injector; a Needle Control Valve and a Spill Valve. Although they are separate circuits, the same fault code is used to identify a fault in the Needle Control Valve circuit and/or the Spill Valve circuit.

Conditions for diagnostic trouble code (DTC):
1) Resistance too high
2) Injector (INJ) activated

Observable symptoms
1) Low Power
2) Uneven operation
3) Abnormal noise
4) Engine is operating on only 3 or 5 cylinders

Probable cause
1) Injector 1
2) Wiring harness between engine control module (ECM) and injector (INJ)

Fuel Injector operation is controlled by the Engine Control Module (ECM). The ECM provides a common supply voltage to injectors 1,2,3 (Bank 1) and there are individual output transistor drivers inside the ECM to control each individual injector?s ground circuits. There are two solenoid circuits within the injector; a Needle Control Valve and a Spill Valve. Although they are separate circuits, the same fault code is used to identify a fault in the Needle Control Valve circuit and/or the Spill Valve circuit.

Conditions for diagnostic trouble code (DTC):
1) Injector (INJ) activated
2) Cylinder balancing data too high

Observable symptoms
1) Low Power
2) Uneven operation
3) Abnormal noise

Probable cause
1) Excessive wear or damage to cylinder liners, piston, or piston rings
2) Valves and rocker arms
3) Camshaft
4) VCB control valve sticking or slow to close
5) Injector 1

Conditions for diagnostic trouble code (DTC):
1) Unexpected electrical response

Observable symptoms
1) Power loss

Probable cause
1) Injector 1
2) EGR System
3) Fuel Quality
4) Low compression

Conditions for diagnostic trouble code (DTC):
1) Unexpected electrical response

Observable symptoms
1) Power loss

Probable cause
1) Injector 3
2) EGR System
3) Fuel Quality
4) Low compression