Notes For Hand-Held Tester

NOTES FOR HAND-HELD TESTER (HHT)
- Fault search with HHT.
Diagnostic trouble code (DTC) memory: Select "Current DTC's". It the actual condition changes, e.g. when wiggling a connector, the change is reported optically and acoustically so that troubleshooting can be performed directly with the 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 "Current DTC's".

- Nominal values.
All nominal values relative to the actual values as shown on the HHT are listed in General Test and Adjustment Data.

- Actual values for engine coolant temperature (ECT), intake air temperature (IAT) and mass air flow (MAF).
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 DTC memory.

- Actual value for engine rpm.
In case of the engine rpm's, the HHT display shows the closed throttle (idle) speed nominal value calculated by the control module on the left, and on the right, the rpm actual value. Both values should differ from each other only slightly. The permissible tolerances are not known.