|
There are two types of P1128/30 codes. Above Limit and Below Limit.
Above Limit means that the A/F is running so lean - at idle, that the DME cannot richen it sufficiently with the maps it contains. Below Limit is the opposite, meaning that the A/f is so rich - at idle, that the DME cannot properly lean it out.
Here's what the DME 7.2 diagnostic manual says about P1128 (and 1130):
Above Limit:
P1128/P1130 - Fuel/air mixture so lean that sensing has reached its rich threshold.
Possible causes:
– Incorrect signal from MAF sensor
– Intake air system leaking
– Fuel pressure too low
– Volume supply of fuel pump too low
– Fuel injectors fouled
– Exhaust system leaking
Below Limit:
P1128/P1130 Fuel/air mixture is so rich that sensing is up to its lean threshold.
Possible causes:
– Incorrect signal from MAF sensor
– Fuel pressure too high
– Fuel injector leaking
– EVAP canister purge valve open
Note:
If DTC P0445 (EVAP canister purge valve – short to ground) is stored in the memory, correct this fault first. An open EVAP canister purge valve can lead to the lean threshold being reached. Contrary adaptation values in connection with misfiring point to adjusted control times - check control times and adjust if necessary. If the fuel tank reserve light is switched on, no fault is entered.
There are values for tests of the various components mentioned. If you want these, PM me with an email and I can get them to you.
|
Threaded Mode
