CITROEN C5 Handbook page 165

C5 - All Types
RECOMMENDATIONS - PRECAUTIONS (AL 4 and 4 HP 20 AUTOMATIC GEARBOXES)
When the ECU detects an erroneous or non-existent value
on input or output :
- It writes the fault in memory.
- For each associated context, it writes the context of the oldest fault
in memory.
- It initiates a back-up mode strategy.
There are two types of back-up modes :
- The ECU makes replacement values available (relating to comfort,
gear selection quality, loss of functions).
- Access to emergency programme (only 3rd ratio and reverse are
available)
NOTE : 4 HP 20 : A snatching may be felt when changing : P/R - N/R - N/D.
Engines : 6FZ - RFN - RHZ - XFX - 4HX
Procedure prior to carrying out repairs (continued)
Reading the fault codes.
Read the fault codes.
No fault codes present :
Carry out a measure of parameters.
Anomalies present :
• YES : Carry out the necessary repairs.
• NO : Read the fault codes – engine ECU
- Carry out a road test.
Following an initialisation of the ECU, for a certain period of time there
may be an inconsistent gear selection quality (while ECU parameters
are adapted to the gearbox).
To achieve a consistent standard, it is necessary to carry out a road test
taking in frequent gear changes (auto-adaptive laws).
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