Observe system-specific differences which are listed with the applicable diagnosis description in the chapter "Prerequisites for testing".
General notes
The following is to be observed when operating the HHT:
The HHT is designed for vehicle on-board voltage of 12 V. It must not be connected to the mains, e.g. 220 V. Operating temperature is -20°C to +60°C, storage temperature is -30°C to +80°C.
Ensure that no strong electro-magnetic fields (e.g. electric welding kit) are in the immediate vicinity, as they may interfere with operation of the HHT. If HHT is installed in driving mode, route cable of multiplexer so that is cannot reach driver footwell.
Front passenger should read out measured values in driving mode.
To plug in test module, unlock module flap and open, insert test module in slot.
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HHT should not be put to improper use. Take care with aggressive fluids such as petrol, brake fluid, etc and protect from splash water.
Use only rechargeable batteries.
Connect Hand-Held Tester in accordance with connection diagram
Voltage supply for HHT takes place via vehicle on-board network 12 V.
HHT is connected to diagnostic socket in vehicle with mulitplexer and adapter cable.
Connect and disconnect HHT to vehicle diagnostic socket only with ignition switched off.
When working in inspection pit or on rear of a vehicle, an extension cable (4.5 m) is available.
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Buzzer
The HHT is fitted with a buzzer:
High tone - Fault message (e.g. test module not connected)
Medium tone - Confirmation of a key-press entry
Low tone - Current fault detected
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HHT system functions
HHT system functions menu is reached by actuating key F1 in opening screen. Adjustments and functions which affect the HHT itself can be made here. The "backspace" key returns to opening screen.
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The keyboard
The F1-F4 function keys are for selection of the selection range located above them on the display, if the corresponding keys are assigned functions. (e.g. YES, NO).
The "backspace" key is active when an action is completed or if previous menu can be returned to.
The "scrolling" forward or backward keys can be used to jump to next or previous display in a display sequence.
The "cursor up" and "cursor down" keys moves cursor to various menu items in a selection menu.
Key not assigned at present.
Print" key (HHT connected to printer)
"Help" key for display of explanatory text is active if help information is available for the current situation. Control unit variants can be interrogated via the "Help" key in the system menu.
"Continue" key (confirms entry or continues procedure).
"Number" keys (0-9) and full stop
( . ) are for inputting figures in data input fields and for positioning cursor.
Mercedes-Benz
6511 5600 XX
Version X.X
Order no. and version
Opening screen
Appears approx. 5 s after connection of HHT to vehicle.
Actuation of continue key ( ) starts test program.
All further information for operation of HHT now appears on display.
JA
NEIN
F1
F2
F3
F4
?
8
4
1
2
0
.
7
9
5
6
3
?
Control unit version
The control unit version installed in vehicle can be checked under "control unit version" item in "functions" menu.
With MB number appearing in display, figure positions 4, 5 and 6 are not shown ( - - - ), they can be read directly from control unit if necessary.
Fault memory
For testing individual control units, first call up "functions" menu then select "fault memory" item. The figures of the fault code stored in the control unit then appear along with their fault texts.
Detection of a fault and its storage are differentiated as follows:
Fault currently existing (current fault)
Fault was existing, but is no longer (stored fault)
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- Briefly occurring faults e.g. loose contact (open-circuit/short-circuit etc.) are also stored in fault memory.
- Fault memory can also contain fault numbers of which the fault cause has already been removed, but the fault code not erased.
Actual values
If an actual value is required for further troubleshooting, "actual values" item in the "functions" menu can be selected. All actual values of control unit to be tested which are available to HHT then appear with their actual value numbers.
Actuation
In order to actuate particular actuators in vehicle from HHT, "actuation" can be selected from "functions" menu.
Always observe safety precautions when actuating components.
If any operations are to be carried out with engine running, handbrake must also be applied and vehicle secured against rolling away.
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Quick test
Quick test has the task of determining control unit installed in vehicle, as well as storing control unit short designation and fault memory contents of control units at the time quick test is carried out. The content of this fault memory which was stored during quick test is called "quick test result".
The "quick test result" remains unchanged over the entire time the HHT is connected to vehicle even if fault memory in a control unit is erased. Fault memory of all control units installed in vehicle can be erased by calling up "erase fault memory of all systems" function in "quick test result" menu or by carrying out a new quick test.
During quick test, faulty and fault-free systems or main function groups are indicated with:
F Indicates faulty systems or main function groups
Indicates fault-free systems or main function groups
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If, during a quick test, a control unit installed in vehicle is not shown in "quick test" menu, check diagnostic cable of affected control unit to diagnostic socket.
A system is fault-free if
- system is connected and
- system acknowledges and
- no faults are stored in system fault memory.
A system is faulty if
- it is part of basic equipment of model series and is not contacted, or
- it is contacted and does not acknowledge at communication attempt, or
- faults are stored in its fault memory.
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Notes on operating HHT
Symbols with HHT screens
Short-circuit
– Short-circuit to ground
+ Short-circuit to positive
–//– Open-circuit
Connect bridge
Connector
F Indicates faulty systems or function groups
Indicates fault-free systems or function groups
With "current" and "stored faults", fault code selected is on a black background.
Actual values
Actuation
Fault environment data
Diagnosis manual