Test Description

The numbers below refer to the step numbers in the diagnostic procedures.

1. 2
   
   This step determines if the IGN relay is suppling a voltage to the THROT CONT fuse.
2. 5
   
   Increasing the engine speed to 3000 RPM aids in locating a shorted throttle actuator motor control circuit. Depending on the polarity of the throttle actuator motor transistors, this DTC may not set with a fault in the control circuits. The throttle actuator motor is a bi-directional DC motor. Raising the engine speed changes the polarity of the transistors in the throttle actuator motor. This occurs because 1 set of the transistors are low, 0 volts, and the other set are high, battery voltage. Therefore, if 1 set of transistors are at a low voltage and the corresponding circuit is shorted low, DTC P1518 will not set. When the polarity of the transistors change this DTC sets. If this DTC does not Fail This ignition, continue to monitor this DTC status while moving related harnesses and connectors.
3. 29
   
   When the TAC module detects a condition within the TAC system, more than TAC system related DTC may set. This is due to the many redundant tests that run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Disconnecting the components during testing may set additional DTCs. Keep this in mind when reviewing the stored information, Capture info.