P0507

P0507-IDLE SPEED PERFORMANCE HIGHER THAN EXCEPTED

Theory of Operation
The objective of the Idle speed Rationality is to monitor the ability to achieve and maintain a steady idle condition. The monitor will judge the functionality of the idle speed control system by monitoring RPM during idle. If RPM does not come within a calibrated deadband of target idle speed, a timer is started. If the timer reaches its maximum threshold without any sign of the RPM trending towards control, a soft failure is generated.

WHEN MONITORED
With the engine running at idle, MAF <250 mg/tdc, air temp >-17.8° C (0° F) and <-7° C (19.4° F) enable after coolant temp >70° C (158° F) or air temp >-7° C (19.4° F), coolant temp >-7° C (19.4° F) <130° C (266° F), canister purge <100% duty cycle, and no VSS, MAF/MAP, ECT, TPS, ETC, CRK Sensor DTCs nor any fuel system or injector DTCs.

SET CONDITION
Engine speed is 200 RPM or more above idle speed for 7 seconds. Two Trip Fault. Three good trips to turn off the MIL.

POSSIBLE CAUSES
- Air induction system
- Vacuum leaks
- Throttle body
- PCM

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

Diagnostic Test

1. ACTIVE DTC

NOTE: If any other DTCs are present, they must be diagnosed and repaired before continuing this test.

Ignition on, engine not running.
With a scan tool, read DTCs.

Q: Is the DTC active at this time?

YES: Go To 2
NO: Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Component Tests and General Diagnostics
Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

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.

Q: Were any problems found?

YES: Repair or replace as necessary. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Go To 3

3. VACUUM LEAKS

Start the engine.
Inspect the vehicle for external vacuum leaks.
Inspect the engine for internal leaks.

Q: Were any vacuum leaks found?

YES: Repair the vacuum leak as necessary. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Go To 4

4. THROTTLE BODY OPERATION

Inspect the throttle body for carbon build up, other restrictions, and a bent throttle plate using a straight edge.
If the throttle plate does not close entirely it may be bent and needs to be replaced.
Verify that the throttle cable between the Accelerator Pedal and APPS is not binding.

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.

While the vehicle is running, lightly tap on ETC Motor, with your hand, and listen for idle to fluctuate.

Q: Were any problems found or did the idle fluctuate while tapping on the ETC Motor?

YES: Repair or replace as necessary. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Go To 5

5. PCM

NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.

Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.

Q: Were there any problems found?

YES: Repair as necessary. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Replace and program the Powertrain Control Module. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test