Notes For Hand-Held Tester (HHT)

Notes for HHT
- Loose connections
Loose connections are stored if they occur several times in a certain time period. Therefore, they can appear only as stored DTC's and never as actual DTC's.
- Nominal values
All nominal values relative to the actual values shown on the HHT are listed in Test and Adjustment Data. Test and Adjustment Data [Specifications]
- Actual value for engine coolant temperature
In case of an open or short circuit, the actual value is immediately replaced by a substitute value which is very close to the actual value. Therefore, a fault can not be recognized clearly. A readout of the fault is possible only via the diagnostic trouble code (DTC) memory.
- Actual value for engine rpm
In case of the engine rpm's, the HHT display indicates under menu selection 3/1 the closed throttle (idle) speed nominal value calculated by the control module on the left and the rpm actual value on the right.
- Actual value for injection quantity
In case of the injection quantity, the HHT display indicates under menu selection 3/2 engine test the injection quantity nominal value calculated by the control module on the left and the injection quantity actual value on the right.
- Actual value for intake manifold pressure
In case of the intake manifold pressure, the HHT display indicates under menu selection 3/2 engine test the intake manifold pressure nominal value calculated by the control module on the left and the intake manifold pressure actual value on the right.

The values should differ from each other only slightly. The permissible tolerances are presently unknown.