P0506

P0506-IDLE SPEED PERFORMANCE LOWER THAN EXCEPTED

For a complete wiring diagram, refer to the Wiring Information.

Theory of Operation

The objective of the Idle "Speed Rationality is to monitor the ability to achieve and maintain a steady idle condition. The Engine Speed Error is calculated by comparing the difference between the Idle Set Speed from the Engine Speed and filtering the result. If engine speed does not come within a calibrated threshold 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 100 RPM or more below idle speed for seven (7) seconds. Two Trip Fault. Three good trips to turn off the MIL.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

Diagnostic Test

1. ACTIVE DTC

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

1. Start the engine.
2. Allow the engine to reach normal 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 possible serious or fatal injury.

3. With a scan tool, select View DTCs.

NOTE: It may be necessary to drive the vehicle to meet the conditions to set this DTC, try to repeat the conditions in which the fault originally set by reviewing the Freeze Frame data.

Is the DTC Active or Pending at this time?

Yes

- Go To 2

No

- Perform the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test.

2. AIR INDUCTION SYSTEM
1. Inspect the Air Induction System for the following problems.
2. Restrictions: Dirty Air Cleaner, Foreign material trapped in the air intake tube, etc.

Were any problems found?

Yes

- Repair or replace as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 3

3. PCV SYSTEM
1. Inspect the PCV system for the following problems:
2. Restrictions - sticking valve, collapsed hoses or tubes, obstructed passages or ports, etc.

Were any problems found?

Yes

- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 4

4. THROTTLE BODY OPERATION
1. Inspect the throttle body for carbon build up, other restrictions, and a bent throttle plate using a straight edge.
2. If the throttle plate does not close entirely it may be bent and needs to be replaced.

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 possible serious or fatal injury.

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

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

Yes

- Verify that there is good pin to terminal contact at the Throttle Body and the Powertrain Control Module connectors. Replace the Throttle Body Assembly if no problems were found in the connectors. Disconnect the Battery when replacing the Throttle Body Assembly. After installation is complete, use a scan tool and select the Throttle Body Self Learn.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 5

5. POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Throttle Body and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched, or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the Throttle Body and Powertrain Control Module harness connectors.
4. Perform any Technical Service Bulletins that may apply.

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.