Volvo Engine Brake VE D12, D12A, D12B. Manual - part 6

Group 25

Troubleshooting

T2008011

When a sufficient number of measurements have been
carried out, set the engine brake switch(es) to the OFF
position and remove the bridge between terminals 2 and
11 at the 36-pin connector.

Hold

pressed in (approximately 2 seconds) until the

text Temp. Display is shown on the display.

T2008014

Press

until the text Temp. Evaluation is shown on

the display.

T2008021

Press

and the first stored measurement value is dis-

played. The identification letter A appears before the
measurement value.

By pressing

it is possible to view all the

values on the display.

By pressing

again, the measurement value stored af-

ter the letter B is displayed.

Group 25

Troubleshooting

T2008022

By pressing

again, the difference between measure-

ment values B and A is shown.

By pressing

it is possible to view all the

values on the display.

Note: If the first measurement value is greater than the
second, the difference between the values will be shown
as a minus value on the display.

T2008020

Press

once.

The first stored value from the second measurement
(value C) is shown on the display.

By pressing

one more time, the measurement value

stored after the letter D is displayed.

By pressing

again, the difference between measure-

ment values D and C is shown.

The results from the third, and if necessary, the fourth
and fifth measurements are produced in the same way
as with measurements one and two.

By pressing

, it is possible to move between 10 mea-

surement values and 5 differences.

Note the measurement results and remember that a fully
charged back-up battery retains the stored measurement
values in the instrument for max. 20 minutes after the
external voltage supply has been broken. If possible, do
not break the voltage supply to the instrument before all
the measurement results have been noted.

T2008015

Hold

pressed in (approx. 2 seconds), when all mea-

surement results have been noted, until the text Temp.
Evaluation is shown on the display.

T2008023

Press

until the display shows the text Temp. Dis-

play.

Group 25

Troubleshooting

T2008024

By holding

pressed in for approximately 2 seconds

until the display shows the text Temperature, the instru-
ment leaves the back-up mode and all the stored
measurement values are cleared.

Note: Make sure that the values are noted before
the instrument is set in position Temperature.

Disconnect the electrical plug for the external voltage
supply.

Note: Switch the instrument off by holding

pressed in

for approx. 2 seconds when the display shows the text
Temp. Evaluation or Temp. Display, after the external
supply contact has been broken.

Do not leave the instrument in battery back-up mode.
The battery will discharge very quickly if the external
voltage supply is broken and the instrument has to rely
on battery back-up.

Evaluate the test.

Evaluation of the Brake Test

When the switch(es) are moved from position OFF to po-
sitions ON/HI, the oil pressure in the rocker arm shaft
should rise to min. 2 bar (29 psi).
If the oil pressure does not exceed 2 bar (29 psi), the
control valve is faulty.

Note: Low oil pressure in the rocker arm shaft may also
be due to excessive wear in the rocker arm bushing
and/or rocker arms which result in excessive oil pressure
loss. See “Rocker Arm Roller, Checking” page 46.

The temperature increase for each individual cylinder
should be between 90

C and 130

C (194

F and 266

in order to be certain that the compression brake on
each cylinder is functioning properly.

If there is no temperature increase, or if the temperature
increase is less than 80

C (176

F) on any individual

cylinder, the compression brake on that cylinder is not
functioning properly.

If the result of a test is not clear, the test must be
repeated. At least three tests should be carried out in or-
der to obtain valid results.

The measured exhaust gas temperature varies between
the cylinders, depending on the position of the cylinders.

The cylinders that are positioned nearest the tur-
bocharger will have a higher measured value than those
at either end of the cylinder block. This is due to the
temperature sensors also being influenced by the pass-
ing air flow from the cylinders furthest away from the
exhaust manifold outlet.

When evaluating the test, this point should also be taken
into consideration.

For example, when comparing cylinders 1 and 6, the
temperature increase should more or less be the same,
providing that the compression brake is functioning prop-
erly on both cylinders.

The same comparison can be made between cylinders 2
and 5 and cylinders 3 and 4.

It should be pointed out that it requires repeated brake
testing to be able to obtain an indication that the braking
effect on a cylinder is reduced.

In instances where there is no braking effect on a cylin-
der, there is also no reference to compare an equivalent
cylinder with.

The less the braking effect is reduced on a cylinder, the
greater the difficulty in identifying the cylinder.

Group 25

Troubleshooting

2531-06-02-01
Engine Brake, Checking

Before working on a vehicle, set the parking brakes,
place the transmission in neutral, and block the
wheels. Failure to do so can result in unexpected ve-
hicle movement and can cause serious personal
injury or death.

WARNING

HOT ENGINE! Keep yourself and your test equipment
clear of all moving or hot engine parts. A hot engine
can cause serious burns or can permanently damage
test equipment.

Note: Before carrying out the following procedure, read
the troubleshooting general information in “Engine Brake,
Fault Tracing” page 15.

Special tools: J–39200 Fluke 87 Multimeter

Measurement 1

W2002218

Move the switch(es) on the instrument
panel to ON/HI (exhaust brake and
compression brake, VEB) positions.

2
Bridge terminals 3 and 10 on the
breakout box. Doing so energizes the
EECU power supply relay by providing
a ground to the coil side of the relay.

3
Set Multimeter to measure Amps and
connect it to terminals 2 and 11 on the
36–pin breakout box. This supplies
battery voltage and measures current
draw to the brake circuit (exhaust
brake only).

4
An audible ”click” should be heard
from the exhaust brake solenoid valve
when the multimeter is connected.

5
If no ”click” is heard from the exhaust
brake solenoid valve, and the exhaust
brake measurement 1 results were
OK, replace the HI/LO switch. Other-
wise, proceed to step 6.

6
Disconnect the connector on the ex-
haust brake solenoid valve.

7
Bridge terminals 3 and 10 on the
breakout box.

8
Set Multimeter to measure Amps and
connect it to terminals 2 and 11 on the
36–pin breakout box.

9
A faint ”click” should be heard from the
compression brake solenoid valve
when the multimeter is connected.

Note: Coolant temperature should be
above 43

C (110

F), otherwise VEB

coolant switch must have a jumper
wire installed.

10
The multimeter should show 0.525
Amp.

11
If no ”click” is heard from the compres-
sion brake solenoid valve, or if the
multimeter does not show the value
0.525 Amp, carry out Measurement 2.

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