Astra
Note:
The IAC INTEGRATOR gives the opening tendency (observance of the pulse duty factor necessary for nominal engine speed) of the idle speed adjuster. This means: 128 steps is the middle of the regulating range, Values > 128 steps mean larger, values < 128 steps mean smaller opening cross-sections.
The IAC INTEGRATOR needs the following information for regulation:
· Engine speed signal (inductive pulse pick-up) · Idle speed contact in throttle valve switch closed · Engine temperature · Reference mark for firing angle (inductive pulse pick-up)
To be able to evaluate a change in the IAC INTEGRATOR, the IAC PULSE RATIO must also be included. If the IAC INTEGRATOR is ouside the tolerance band, the IAC PULSE RATIO tries to correct the integrator. If the IAC PULSE RATIO is also outside the tolerance band at a constant value, trouble-shooting should be introduced.
Trouble-shooting: Nominal Value: Cause of Fault: First check correct adjustment of throttle valve switch and Test Step 12 ENGINE SPEED
· Read out IAC PULSE RATIO 34 to 80 % Read out IAC INTEGRATOR 127 to 135 steps · If IAC PULSE RATIO is constantly · Lack of air > 80 % - Idle speed adjuster sticks, does not open and - Bypass air hose blocked or kinked > 128 steps - Carry out F5:ACTUATOR TEST, test step 01
· If IAC PULSE RATIO is constantly · Excess air < 34 % - Throttle valve open and - Accelerator cable or throttle valve jams < 128 steps - Idle speed adjuster jams, does not close - Carry out F5:ACTUATOR TEST, test step 01
Air loss (leaks at throttle body, intake system, bypass lead)
Other Causes of Faults: · Control unit defective Checking, see Table 5 F5:ACTUATOR TEST, test step 01)
· Mass air flow sensor defective (Checking, see test step 05)
· Throttle valve switch defective (Checking, see test step 07)
· Mixture too rich (Checking, see test step 25)
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