Volvo Symptom D12D US02 Service Manual page 17

Group 20
Step 4: Component and Function Checks
Action:
Check that the fuel quality is within specifications.
Check for air in the fuel system.
Check for carbon monoxide in the fuel.
Check the fuel pump for damage or abnormal wear including axial play.
Check that the valves for the fuel supply pump function correctly.
Check that the fuel supply pressure is within specifications from idle to high engine
speeds.
Check the power supply/ground and wiring harness for engine ECU, including connectors
and terminal pins for damage or oxidation.
Check that the EECU receives the correct signals from the flywheel and camshaft
sensors.
Check the EPG and AVU. Check the function, signal input, power supply, and air supply.
Check that the oil pressure for the rocker arm shaft is within specifications when the
VCB is non-active.
Note: If either valve or solenoid has failed allowing full system oil pressure
to the rocker arm shaft, this results with low cylinder compression. The
VCB rocker arms are opening the exhaust valves at inappropriate times,
which leads to black smoke and engine starting problems.
"Engine Difficult to Start" page 5
D
C2002641
Refer to:
Group 23: Fuel Quality, Checking
Group 23: Air in the Fuel System, Checking
Group 23: Carbon Monoxide in the Fuel, Checking
"Fuel Supply Pressure, Fault Tracing"
(Checklist B), Impact or ID DVD: Information type
"Diagnostics" group 2309.
"Fuel Supply Pressure, Fault Tracing"
(Checklist B), Impact or ID DVD: Information type
"Diagnostics" group 2309.
"Fuel Supply Pressure, Fault Tracing"
(Checklist B), Impact or ID DVD: Information type
"Diagnostics" group 2309.
"Engine ECU, Fault Tracing"
Impact or ID DVD: Information type "Diagnostics",
group 2841.
Group 30: Wiring, connectors, and terminals,
checking.
"Cam and Flywheel Signals, Fault Tracing"
(Checklist H), Impact or ID DVD: Information type
"Diagnostics", Group 2846.
"Exhaust Pressure Governor, Fault
Tracing"
(Checklist E), Impact or ID DVD:
Information type "Diagnostics", group 2538.
"Rocker Arm Shaft Oil Pressure, Checking"
(Checklist O), Impact or ID DVD: Information type
"Diagnostics" group 2531.
(Checklist M),
13