FixVault

DTC P151B-00: IAC System Problem: Notes

DETECTION CONDITION AND POSSIBLE CAUSE

DTC P151B:00 IAC system problem
DETECTION CONDITION 
  • The PCM cannot control the idle speed toward the target idle speed during the KOER self test.

Diagnostic support note 
  • The check engine light does not illuminate.
  • FREEZE FRAME DATA (Mode 2)/Snapshot data is not available.
  • The DTC is stored in the PCM memory.
FAIL-SAFE FUNCTION  -
POSSIBLE CAUSE 
  • A/C magnetic clutch malfunction
  • Drive-by-wire control system related sensor malfunction
    • TP sensor malfunction
  • Purge solenoid valve malfunction
  • Air cleaner element restricted
  • Throttle body passage blockage
  • Engine malfunction
    • Insufficient engine compression (over capacity of blow-by gas)
    • Poor quality fuel
  • Generator malfunction
  • PCM malfunction
SYSTEM WIRING DIAGRAM  -
CAUTION:
  • Verify the malfunction symptom according to not only the PID value but also the symptom troubleshooting.
RELATED PIDS

Monitor item (Definition) Unit/Condition Condition/Specification (Reference)
ALTF %
  • Switch the ignition to ON: 0 % 
  • Idle: approx. 42 % 
  • Racing (engine speed is 2,000 rpm): approx. 29 % 
ALTT V V
  • Idle (no E/L): approx. 14 V  (this is an internal calculation value and differs from the terminal voltage).
TP1 V
  • Accelerator pedal released: approx. 1.11 V 
  • Accelerator pedal depressed: approx. 4.59 V 
%
  • Accelerator pedal released: approx. 22 % 
  • Accelerator pedal depressed: approx. 92 % 
TP2 V
  • Accelerator pedal released: approx. 3.92 V 
  • Accelerator pedal depressed: approx. 0.41 V 
%
  • Accelerator pedal released: approx. 22 % 
  • Accelerator pedal depressed: approx. 82 %