P099

Diagnostic Trouble Code P099:

Cruise Control Circuit:

CIRCUIT DESCRIPTION
This diagnostic test monitors the cruise control servo position sensor to ensure that the servo has released the throttle after the cruise control has been disengaged for 2 seconds. If the cruise control servo has not released, Code P099 will set and engine power will be reduced by disabling fuel to individual cylinders. Code P068 may disable cruise control and lead to setting Code P099.

NOTE: Conditions for code set change depending on whether the code was previously set.

TEST CONDITIONS
1. Engine running.
2. PS07 override not active.

FAILURE CONDITIONS
Code P099 not previously set.
1. Cruise control disengaged for 2 seconds.
2. Throttle angle greater than 20 degrees, Throttle Position (TP) sensor not failed;
OR
Manifold Absolute Pressure (MAP) greater than 70 kPa, TP sensor failed.
3. Cruise control servo stroke greater than 63% for 0.1 second.

Code P099 previously set.
1. Cruise control disengaged for 2 seconds.
2. Throttle angle greater than 16 degrees, TP sensor not failed;
OR
MAP greater than 55 kPa, TP sensor failed.
3. Cruise control servo stroke greater than 37% for 0.1 second.

ACTION TAKEN
1. "Reduced Engine Power" message is displayed on the Driver Information Center (DIC).
2. Powertrain Control Module (PCM) will disable fuel to individual cylinders to reduce engine power.

NOTES ON FAULT TREE
1. Checking if PCM can control the cruise control solenoid.
2. Checking if cruise control servo position sensor is working correctly.
3. Checking if cruise control servo will extend fully. If it does not, check CKT 402 for a short to voltage.

NOTES ON INTERMITTENTS
Code P099 may be inadvertently induced by a technician using the cruise servo to "bump" the throttle.