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Home >> Chevrolet >> 2001 >> Camaro Base, 2D Convertible, Automatic >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 2 (Engine Control System Self-Diagnostics - 5.7L) >> Diagnostic Tests >> DTC P0506: Idle Speed Low >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different variant/trim than selected.
  1. If powertrain diagnostic system check was performed, go to next step. If powertrain diagnostic system check was not performed, go to POWERTRAIN DIAGNOSTIC SYSTEM CHECK  under DIAGNOSTIC SYSTEM TESTS. After performing powertrain diagnostic system check, go to next step.
    NOTE: Verify engine speed stabilizes with each commanded RPM change so PCM can determine if engine speed stays within 100 RPM of commanded RPM.
  2. Set parking brake and block drive wheels. Start engine. Turn off all accessories. Using scan tool, command RPM from idle RPM up to 1800 RPM, then 1800 RPM to 600 RPM. Repeat 2 times and exit from test. If engine RPM change responds to within 100 RPM of each commanded RPM, go to next step. If engine RPM change does not respond to within 100 RPM of each commanded RPM, go to step  4.
  3. Turn ignition on. Using scan tool, review FREEZE FRAME and/or FAILURE RECORDS data and note parameters. Turn ignition off for at least 30 seconds. Start engine and operate vehicle within conditions required for this diagnostic to run, and as close to conditions recorded in FREEZE FRAME and/or FAILURE RECORDS as possible. Select DTC function, then enter this DTC. If scan tool indicates that this test failed this ignition, go to next step. If scan tool does not indicate that this test failed this ignition, see DIAGNOSTIC AIDS .
  4. Turn ignition off. Locate and disconnect IAC valve connector. See Figure. Connect IAC Motor Driver (J 37088-A) to IAC valve (component side). Start engine. Using IAC motor driver, command IAC valve in until 600 RPM is reached. Then command IAC valve out until 1800 RPM is reached. Using scan tool as a guide, command IAC valve in until engine RPM matched scan tool desired idle speed. If engine RPM increased and decreased steadily and smoothly, go to next step. If engine RPM did not increase and decrease steadily and smoothly, go to step  10.
  5. Turn engine off. Connect a test light between ground and any terminal of IAC valve connector. Start engine. Monitor scan tool IAC counts. Using IAC motor driver, command IAC valve in to decrease engine RPM until IAC counts on scan tool start to increment. Then command IAC valve out to increase engine RPM until IAC counts on scan tool start to increment. Using scan tool as a guide, command IAC valve in until engine RPM matched scan tool desired idle speed. Move test light to another terminal of IAC valve connector and repeat test until test light has been connected to all 4 terminals of IAC valve connector. If test light remains on (never flashing) at any terminal while IAC counts on scan tool are incrementing, go to step  9. If test light does not remain on (never flashing) at any terminal while IAC counts on scan tool are incrementing, go to next step.
  6. If test light remains off (never flashing) at any terminal while IAC counts on scan tool are incrementing, go to step  8. If test light does not remain off (never flashing) at any terminal while IAC counts on scan tool are incrementing, go to next step.
  7. Connect test light between IAC valve connector terminals "C" (Light Blue/Black wire) and "D" (Light Blue/White wire). Monitor scan tool IAC counts. Using IAC motor driver, command IAC valve in to decrease engine RPM until IAC counts on scan tool start to increment. Then command IAC valve out to increase engine RPM until IAC counts on scan tool start to increment. Monitor test light operation while IAC valve counts are incrementing. Using scan tool as a guide, command IAC valve in until engine RPM matched scan tool desired idle speed. Move test light to IAC valve connector terminals "A" (Light Green/Black wire) and "B" (Light Green/White wire) and repeat test. Using scan tool as a guide, command IAC valve in until engine RPM matched scan tool desired idle speed. If test light remains on (never flashing) while IAC counts on scan tool are incrementing, go to DIAGNOSTIC AIDS . If test light does not remain on (never flashing) while IAC counts on scan tool are incrementing, go to step  14.
  8. Turn engine off. Locate PCM and disconnect connector C2. See Figure. Check for open in suspect circuit where test light remained off. See IDLE AIR CONTROL VALVE CIRCUIT IDENTIFICATION  table. Repair as necessary. After repairs, go to step  15. If circuit is okay, go to step  11.
  9. Turn engine off. Turn ignition on. Locate PCM and disconnect connector C2. See Figure. Check for short to voltage in suspect circuit where test light remained off. See IDLE AIR CONTROL VALVE CIRCUIT IDENTIFICATION  table. Repair as necessary. After repairs, go to step  15. If circuit is okay, go to step  11.
  10. Check for throttle body damage or evidence of tampering. Check for restricted air filter, throttle body screen or air intake system duct. Remove IAC valve and check for clogged air passage. See REMOVAL, OVERHAUL & INSTALLATION - CARS article. Check for excessive deposits on throttle body plate, throttle bore and IAC valve pintle. Repair as necessary. After repairs, go to step  15. If components are okay, go to step  12.
  11. Check for poor connections at PCM. Repair as necessary. After repairs, go to step  15. If connections are okay, go to step  14.
  12. Check for poor connections at IAC valve. Repair as necessary. After repairs, go to step  15. If connections are okay, go to next step.
  13. Replace IAC valve. After repairs, go to step  15.
  14. Replace PCM. See REMOVAL, OVERHAUL & INSTALLATION - CARS article. After repairs, go to next step.
  15. Using scan tool, clear DTCs. Turn ignition off for at least 30 seconds. Start engine and allow it to reach normal operating temperature. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step  2.
  16. Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no undiagnosed DTCs are displayed, system is okay.
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