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Volvo Engine Brake VE D12, D12A, D12B. Manual - part 4

Group 25

Troubleshooting

Electrical Troubleshooting

W2002196

Special tools: J–41132

Connecting test equipment

Make sure that the ignition key is in the ”OFF” posi-
tion.

Clean the area around the EECU and harness con-
nectors.

Disconnect the EB harness (lower harness). Inspect
the harness for corrosion and damage to the con-
nector housing, terminals, and seal. Repair as
required.

Connect the 36–pin breakout box to the EB harness
only.
Make sure the harness connectors are properly
pressed together. Do not force connectors together.

Note: Do not connect the breakout box to the
EECU.

Group 25

Troubleshooting

Voltage measurement

Conditions:

•

Engine running

•

Engine brake switch in the ON position

•

Selector switch in the HI position

•

Throttle pedal in idle position

•

Clutch pedal released

•

ABS not activated

•

PTO not activated

•

Vehicle speed greater than 3.2 km/h (2 mph)

•

Sufficient coolant temperature, see table page 12.

Voltage Measurement

36-Pin Box Selection

Intended Value

Probable Cause

Engine brake supply (if all
conditions are met)

2:9

B+

Faulty connection

Faulty engine brake
switches

Faulty harness

Resistance measurement

Conditions for Resistance Measurements:

•

Ignition off

•

Engine not running

•

Engine brake switch in the ON position

Note: Values in table apply to solenoid valve with
part no 1610563 and 1610567.
For solenoid valves with part numbers 8143014 and
8143018, please refer to:

Service
Manual

PV776–280–600SM
Electronic Controls, VE D12, D12 A,
D12 B

Resistance Measurement

36-Pin Box Se-
lection

Intended
Value

Probable Cause

Solenoid valve, exhaust brake (engine
brake selector switch in LOW position

2:9

13 – 16

Faulty connection

Faulty harness

Solenoid valve (exhaust brake)

Faulty exhaust brake

Faulty engine brake switches

Solenoid valve exhaust brake and
compression brake (engine brake se-
lector in HI position)

2:9

7.5 – 9.5

Faulty connection

Faulty harness

Solenoid valve (compression brake)

Faulty engine brake switches

Faulty VEB coolant temperature switch

Note: If the multimeter shows 20–22

when the engine

brake select switch is in the HI position, the exhaust
brake solenoid valve is damaged.

Group 25

Troubleshooting

Mechanical Troubleshooting

Conditions

•

The electrical troubleshooting has been carried out,
or any possible faults in the electrical system can be
completely eliminated.

•

The truck has full pressure [827 kPa (120 psi)] in
the air system.

•

The engine has normal oil pressure.

•

The engine coolant temperature is at operating tem-
perature.

Service procedures not contained in this informa-
tion are to be found in the service information for
the VOLVO D12 engine under the respective group.

Exhaust brake

Compression brake

Test 1

Test 2

Test 3

Test 2

Test 4

Test 5

Carry out the tests on the exhaust brake and com-
pression brake in numerical order according to the
above diagram, when either one of the brake sys-
tems does not work.

If both brake systems work, but give poor braking ef-
fect, see “Low Engine Braking Effect (VEB)” page 21.

Group 25

Troubleshooting

VEB Troubleshooting, Order to
Follow

If the fault remains after correcting any indicated fault
codes, and the engine and electrical system function
normally, troubleshooting should be performed in the fol-
lowing order:

Begin troubleshooting by attempting to establish which of
the brake systems is faulty (exhaust brake, compression
brake, or both systems).

Verify that the following preconditions for exhaust brak-
ing are satisfied, with the switch(es) on the instrument
panel in the ON/LOW (exhaust brake only) positions.

•

Accelerator pedal position at 0% (idle position)

•

Clutch pedal not depressed

•

Engine speed should be greater than 1100 RPM

•

PTO not activated

•

Vehicle speed should be greater than
3 km/h (2 mph).

•

Anti-lock Braking System (ABS) not activated.

•

Boost pressure less than 150 kPa (22 psi).

Note: The exhaust brake will engage only when all of
these preconditions are satisfied.

Note: When the exhaust pressure governor (EPG) is ac-
tivated in conjunction with starting, running the engine
warm, and keeping the engine warm, other preconditions
apply.

Verify that the following preconditions for VEB (exhaust
braking and compression braking) are satisfied, with
the switches on the instrument panel in the ON/HI (ex-
haust brake and compression brake, VEB) positions.

•

Accelerator pedal position at 0% (idle position)

•

Clutch pedal not depressed

•

Engine speed should be over 1100 RPM

•

PTO not activated

•

Vehicle speed should be greater than 3 km/h
(2 mph).

•

Anti-lock Braking System (ABS) not activated.

•

The coolant temperature should be over 43

(110

F), otherwise only the exhaust brake will be

engaged.

•

Boost pressure less than 150 kPa (22 psi).

Note: An additional option is to have the VEB enable au-
tomatically if the vehicle exceeds a specified cruise
control limit. If this option is selected, the VEB will auto-
matically engage at a selectable speed approximately
6.4 to 32 km/h (4 to 20 mph) above the set cruise con-
trol speed.

Always begin with electrical troubleshooting, unless
a fault in the electrical system can be completely
ruled out.

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