AIRBAG - SEAT BELT PRETENSIONERS
Fault finding - Introduction
88C
88C - 3V3 MR-372-J84-88C000$010.mif
AIRBAG ACU4
Vdiag: 04
3. REMINDERS
Procedure:
To run diagnostics on the vehicle's computers, switch on the ignition in fault finding mode (+ after ignition forced
setting):
– vehicle card in card reader.
– Press and hold start button (longer than 5 seconds) with start-up conditions not fulfilled,
– Then connect the diagnostic tool and perform the required operations.
+ After ignition feed cut-out is performed as follows:
– Disconnect the diagnostic tool,
– Press the start button twice briefly (less then 3 seconds),
– See that the + after ignition feed has been cut off by checking that the computer warning lights on the instrument
panel have gone out.
Faults:
Faults are declared to be either present or stored (depending on whether they appeared in a certain situation and
have disappeared since, or whether they remain but are not diagnosed within the current context).
The present or stored state of faults should be taken into consideration when the diagnostic tool is used after the
+ after ignition feed (without acting on the system components).
Deal with present faults according to the procedure specified in the Interpretation of faults section.
For stored faults, note the faults displayed and follow the instructions in the "Notes" section.
If the fault is confirmed when the instructions in the Notes section are applied, the fault is present. In this case, deal
with the fault
If the fault is not confirmed, carry out basic checks. Check:
– the electrical lines which correspond to the fault,
– the connectors for these lines (for oxidation, bent pins, etc.),
– - the resistance of the faulty component,
– the condition of the wires (melted or cut insulation, wear).
or use the fault finding procedure to check the circuit of the faulty component.
Conformity check
The conformity check is designed to check the states and parameters which do not display any faults on the
diagnostic tool when inconsistent. This phase therefore:
– diagnosis of faults that do not have a fault display, and which may correspond to a customer complaint.
– checks that the system is operating correctly and that there is no risk of a fault reappearing after repairs.
This section gives the fault finding procedures for states and parameters and the conditions for checking them.
If a state is not behaving normally or a parameter is outside permitted tolerance values, you should consult the
corresponding fault finding page.
Customer complaints – Fault finding charts
If the diagnostic tool check is correct, but the customer complaint persists, it should be dealt with according to the
customer complaint.IMPORTANT
The left-hand and right-hand Xenon bulb computers are powered when the dipped headlights are lit. Fault finding
procedures can only be carried out on them after the ignition has been switched on in fault finding mode (+ after
ignition imposed) and the dipped headlights are on.
A synopsis of the general procedure to follow is provided on the following
page in the form of a logic flow chart.
ACU4 Vdiag04 J84 1.0
