P0507-IDLE SPEED PERFORMANCE HIGHER THAN EXPECTED
For a complete wiring diagram Refer to Section 8W.
Theory of Operation
The objective of the Idle Speed Rationality monitor is to evaluate the ability of the idle speed control system to achieve and maintain a steady idle, by monitoring engine RPM during idle. If engine RPM is not within a calibrated deadband of target idle speed, a timer is started. If the timer reaches a maximum threshold without any sign of the RPM trending towards control, a fault is generated.
- When Monitored:
With the engine idling in drive, the brake applied, MAF below 250 mg/tdc, air temp above -17.8° C (0° F), coolant temp is above 70° C (158° F), Evap purge below 100% duty cycle, and no VSS, MAF/MAP, ECT, TPS, ETC, CKP Sensor, fuel system, or injector DTCs present.
- Set Condition:
Engine speed is 175 RPM or more above target idle speed for 30 seconds. Two Trip Fault. Three good trips to turn off the MIL.
| Possible Causes |
| AIR INDUCTION SYSTEM LEAKS OR RESTRICTIONS |
| PCV SYSTEM LEAKS OR RESTRICTIONS |
| ENGINE VACUUM LEAKS |
| THROTTLE BODY |
| POWERTRAIN CONTROL MODULE (PCM) |
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).
Diagnostic Test
1. ACTIVE DTCNOTE: It is possible for ETC DTCs to be set at the same time as this DTC. Proceed with this test only if the other DTCs that are present are ETC related, but clear them before proceeding. If any other DTCs are set, they must be diagnosed and repaired before continuing this test.
Start the engine and allow it to reach operating temperature.
WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in personal injury or death.
With a scan tool, select View DTCs.
Is the status Active for this DTC?
Yes
- Go to 2
No
- Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)
2. AIR INDUCTION SYSTEM
Inspect the air induction system for the following problems:
Restrictions - dirty air cleaner, foreign material trapped in the air intake tube, etc.
Leaks - air intake tube connection, air cleaner housing, etc.
Were any problems found?
Yes
- Repair as necessary.
- Perform the PCM Verification Test. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No
- Go to 3
3. PCV SYSTEM
Inspect the PCV system for the following problems:
Restrictions - sticking valve, collapsed hoses or tubes, obstructed passages or ports, etc.
Leaks - cracked or damaged hoses or tubes, poor hose or tube connections, PCV valve stuck open, etc.
Were any problems found?
Yes
- Repair as necessary.
- Perform the PCM Verification Test. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No
- Go to 4
4. ENGINE VACUUM LEAKS
WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in personal injury or death.
Start the engine.
Inspect the engine for external vacuum leaks.
Inspect the engine for internal leaks.
Were any problems found?
Yes
- Repair as necessary in accordance with the Service Information.
- Perform the PCM Verification Test. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No
- Go to 5
5. THROTTLE BODY OPERATION
WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in personal injury or death.
Inspect the throttle body for carbon build up or other restrictions.
Using a straight edge, verify that the throttle plate is not bent. If the throttle plate is bent, the throttle body must be replaced.
Start the engine.
While the engine is running, lightly tap on the ETC Motor, and listen for the idle to change. If the idle changes, the throttle body must be replaced.
Were any problems found?
Yes
- Repair as necessary.
- Perform the PCM Verification Test. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No
- Go to 6
6. POWERTRAIN CONTROL MODULE (PCM)
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the throttle body and the Powertrain Control Module (PCM).
Look for any chafed, pierced, pinched, or partially broken wires.
Look for broken, bent, pushed out or corroded terminals.
Refer to any Technical Service Bulletins that may apply.
Were any problems found?
Yes
- Repair as necessary.
- Perform the PCM Verification Test. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No
- Replace and program the Powertrain Control Module (PCM) in accordance with the Service Information.
- Perform the PCM Verification Test. (Refer to 9 - ENGINE - STANDARD PROCEDURE)