Code P030, ISC Rpm Out Of Range: Action

PCM turns on MIL.

1. Checks for ISC motor codes that can cause other problems.
2. Checks if cruise control is engaged, causing idle problems.
3. Checks for proper ISC motor operation.
4. Many engine fuel and emissions system faults may cause unstable idle. If base engine idle is not steady, ISC may not be able to control idle to within the range of commanded idle speed.
5. Checks PCM's ability to control ISC motor by checking for signal present at ISC motor.
6. Checks for open or short to ground in circuit No. 425 or 426.
7. Checks PCM's ability to control ISC motor by checking for signal present at ISC motor.
8. Checks if ISC motor is receiving signal but not responding correctly. Voltage should fluctuate continuously from negative to positive value.

Fig 1: Code P030 Schematic, ISC RPM Out Of Range

Courtesy of GENERAL MOTORS CORP.

Fig 2: Code P030 Diagnostic Flow Chart - 1 Of 2, ISC RPM Out Of Range

Courtesy of GENERAL MOTORS CORP.

Fig 3: Code P030 Diagnostic Flow Chart - 2 Of 2, ISC RPM Out Of Range

Courtesy of GENERAL MOTORS CORP.