C4.4 and C6.6 Industrial Engines and Engines for Caterpillar Built Machines Caterpillar

Note: Use this procedure only if the engine speed does not change. This fault will not occur in a generator set application.

Probable Causes

• Diagnostic codes

• Multi-position throttle switch

• Throttle position sensor

Recommended Repairs

Diagnostic Codes

Check for active diagnostic codes on the electronic service tool. Troubleshoot any active codes before continuing with this procedure.

Use the electronic service tool to check the setup of the throttle.

Multi-position Throttle Switch

Note: When the engine is operating and the fault occurs, the configuration of the throttle will not change. The configuration of the throttle only needs to be checked if the engine has never run.

If a fault in the multi-position throttle switch is suspected, refer to Troubleshooting, "Throttle Switch Circuit - Test".

Throttle Position Sensor

Refer to Troubleshooting, "Analog Throttle Position Sensor Circuit - Test" or Troubleshooting, "Digital Throttle Position Sensor Circuit - Test" if any of the following diagnostic codes are active:

• 0041-03 8 Volt DC Supply voltage above normal

• 0041-04 8 Volt DC Supply voltage below normal

• 0091-08 Throttle Position Sensor abnormal frequency, pulse width or period

• 0774-08 Sec Throttle Position Sensor abnormal frequency, pulse width or period