Circuit Description
This diagnostic test is used to determine if the idle control system is maintaining the proper idle speed. The IAC system controls idle speed by allowing a certain amount of air to bypass the throttle body, the throttle plate is closed during idle, through the IAC valve. The PCM controlled IAC motor moves a pintle in and out of the IAC valve, thus varying the amount of air entering the intake manifold. By varying the amount of air intake, different idle speeds can be achieved. When the pintle is in, the valve is closed and low idle speeds result. When the pintle is out, the valve is open and high idle speeds occur. If the actual engine idle speed is more than the desired idle speed and all test conditions are met DTC P0507 will set.
Conditions for Setting the DTC
Test Conditions
| • | DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208 and P0502 not set. |
| • | DTCs P1370, P1371, P1406 or P1441 not testing. |
| • | PCM not checking EGR operation. |
| • | Ignition voltage between 10.5 and 15 volts. |
| • | BARO at least 65 kPa. |
| • | ECT is between -20°C (-4°F) and 110°C (230°F). |
| • | Engine running for at least 10 seconds. |
| • | PCM in Closed Loop fuel control. |
| • | MAF between 2 and 35 grams per second. |
| • | Actual idle speed greater than desired idle speed by at least 80 RPM. |
| • | Throttle position 0.6 degrees or less. |
| • | Calculated throttle position switch closed. |
| • | Vehicle not moving. |
| • | A P/N to D/R or a D/R to P/N transition has not occured within the last 60 seconds. |
Failure Condition
Actual idle speed is more than 80 RPM higher than the desired idle speed for 15 seconds.
Action Taken When the DTC Sets
| • | The Malfunction Indicator Lamp (MIL) will not illuminate. |
| • | The PCM will command a message to be displayed. |
| • | The PCM may record operating conditions at the time the diagnostic fails. This information will be stored in the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn the message OFF after one run and pass of the diagnostic test. |
| • | A History DTC will clear after forty consecutive warm-up cycles with no failures of any non-emission related diagnostic test. |
| • | A Last Test Failed (current) DTC will clear when the diagnostic runs and does not fail. |
| • | Use a scan tool to clear DTCs. |
| • | Interrupting PCM battery voltage may or may not clear DTCs. This practice is not recommended. Refer to Clearing Diagnostic Trouble Codes in PCM Description and Operation. |
Diagnostic Aids
This DTC (and a high idle) could be caused by a noisy Power Steering Pressure (PSP) switch or an intermittently open circuit. If a faulty PSP switch or a faulty connection is suspected disconnected the switch and jumper the terminals together (harness side) if the idle returns to normal or the DTC passes then the PSP switch or connection is faulty.
Step | Action | Value(s) | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to A Powertrain On Board Diagnostic (OBD) System Check | |||||||||
2 | Using a scan tool. Are any other DTCs set? | -- | Go to DTCs that are set | |||||||||
3 |
Does the Engine Speed remain within the specified value of Desired Idle for each RPM command? | 50 RPM | Fault not present. Refer to Diagnostic Aids | |||||||||
4 |
Does each node light cycle red and green (never OFF)? | -- | ||||||||||
5 |
Was a problem found and repaired? | -- | Go to Powertrain Control Module Diagnosis for Verify Repair | |||||||||
6 | Visually/physically inspect for the following conditions:
Do any of the above require a repair? | -- | Refer to appropriate section for on-vehicle service. | |||||||||
7 | Check for poor terminal contact at the IAC harness connector. Was a problem found and repaired? | -- | Go to Powertrain Control Module Diagnosis for Verify Repair | |||||||||
8 | Replace the IAC valve. Is the repair complete? | -- | Go to Powertrain Control Module Diagnosis for Verify Repair | -- | ||||||||
9 | Check terminal contact at the PCM connector C1 terminals 8, 9, 10 and 11. Repair terminal contact if needed. Was terminal contact repaired? | -- | Go to Powertrain Control Module Diagnosis for Verify Repair | |||||||||
10 | Replace the PCM. Refer to PCM Replacement/Programming . Is the repair complete? | -- | Go to Powertrain Control Module Diagnosis for Verify Repair | -- |
