Fuel System Diagnostics - Volvo 240 1989 Service Manual

Design and function
Fuel system LH2.4 - 240
®
Fuel system diagnostics
The fuel system has a built-in self-diagnostic system
and a funclions testing system _ It uses the same
diagnostic socket as the ignition system and Is lo­
cated behind the Ie" spring strut tower in the engine
compartment.
The diagnostic system uses socket 2 for the fuel sys­
tem and socket 6 for the ignition system.
There are eighteen different fault codes in the diag­
nostic system. It is capable of storing up to three fuel
system faults.
The fuel system control unit carries out continuous
checks of the following functions while the engine is
running:
- The control unit's own internal functions .
- Lambda-sond and Lambda settings.
- Coolant temperature sensor.
- Air mass meter.
- Battery voltage.
- Throttle shutter.
- Ignition settings and engine rpm (through Ihe
ignition system control unit).
- Speedometer.
- Knock indicator.
- Idle speed air valve.
- Injectors.
Faults in any of these funclions are registered in the
diagnostic system memory .
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