Logan X90, Assembly, Page: 187 / 231

17B - 34
PETROL INJECTION
Catalytic converter fault finding
L90, and K7J, and 710 – L90, and K7M, and 710
17B
FOR VEHICLES FITTED WITH O.B.D:
The purpose of catalytic converter fault finding is to de-
tect a malfunction which would cause hydrocarbon pol-
lutant emissions to exceed the On Board Diagnostic
limit.
The ability of the catalytic converter to store oxygen in-
dicates its condition. As the catalytic converter ages, its
ability to store oxygen reduces along with its ability to
treat pollutant gases.
I -CONDITIONS FOR ENTERING FAULT FINDING
MODE
Fault finding of the catalytic converter can only take pla-
ce after the engine has been running for the time de-
tailed in the following table, if all the conditions prior to
switching on the ignition are satisfied and maintained:
- no electrical faults,
- cylinder recognition done,
- no misfiring detected,
- no catalytic converter fault finding performed since the
ignition was switched on,
- programming has been done,
- main loop and double loop active,
- coolant temperature above 75˚C.
II - FAULT DETECTION
Fault finding is performed over a stabilised range in fifth
gear at 43 mph (70 km per hour). When the conditions
for starting fault finding are met, richness excitation
peaks are applied, which has the effect of sending
bursts of oxygen into the catalytic converter. If the cata-
lytic converter is in good condition it absorbs the oxy-
gen and the downstream oxygen sensor value will
remain at its average value. If it is in poor condition, it
rejects the oxygen and the lambda sensor voltage os-
cillates. If the fault is confirmed on three consecutive
occasions, the On Board Diagnostic warning light co-
mes on.
The test duration cannot exceed 52 seconds.
If after the test, the diagnostic tool has detected a
functional fault of the catalytic converter, see fault fin-
ding procedure associated with this symptom.
III - CONFIRMATION OF REPAIR
- E T 1 0 3 « Catalytic converter included »:
« ACTIVE »,
- ET107 « Catalytic converter done »: « ACTIVE »,
- no catalytic converter operating fault detected.
Engine Speed, mph
(kph) Engine speed
(rpm) Manifold pres-
sure (mbar) Stabilisation
time (seconds) Time before
authorisation
(minutes)
K7M 63 to 130 1,856 to 3,808 400 to 750 11 17
K7J 63 to 130 1,856 to 3,808 380 to 650 11 17
WARNING
At the end of each test, it is essential that the igni-
tion is not switched off before the result is read on
the diagnostic tool. Switching off the ignition will
lead to the results being misinterpreted.