Chart 8

Lack/Loss of Power

NOTE: Verify the symptom is reported under normal driving conditions without excessive engine or vehicle load. Also, be aware of the engine RPM/speed limiting functions of the PCM.

NOTE: For vehicles equipped with a knock sensor, a lack of power may result when the vehicle is operated with a breakout box installed at the PCM. The knock sensor circuits are not shielded in the breakout box, and knock sensor signal noise may be noticed by the PCM. If this happens, spark timing will be retarded and a lack of power may result.

SYSTEM/COMPONENT	REFERENCE (PINPOINT TESTS -- GASOLINE MODELS article unless noted)
Automatic Transmission Fluid	Visual
Throttle Linkage	Visual
Air Cleaner Element	Visual
Check the following PIDS: DPFEGR (if equipped) (hot idle value within 0.15 volt of key ON, engine OFF value) LONGFT1/LONGFT2 (value between -20 and +20%) IMTVF (if equipped): For both key ON, engine OFF and key ON, engine running with the transmission in PARK/NEUTRAL and the engine RPM greater than 3,000 RPM, the PID should indicate no fault (or NO) in both situations.	DPFEGR PID value not within 0.15 volt of key ON, engine OFF value: For vehicles equipped with an ESM, GO to Pinpoint Test HH . For all others, GO to Pinpoint Test HE . LONGFT1/LONGFT2 value low (-): Continue diagnosis. Concentrate checks in areas that would cause the engine to run rich. LONGFT1/LONGFT2 value high (+): Continue diagnosis. Concentrate checks in areas that would cause the engine to run lean. IMTVF PID indicates a fault: GO to Pinpoint Test HU .
Fuel Delivery System	GO to Pinpoint Test HC .
Secondary Ignition	For vehicles equipped with a coil pack ignition system, GO to Pinpoint Test JC . For all others, GO to Pinpoint Test JB .
MAF Sensor	GO to Pinpoint Test DC .
Exhaust System	GO to Pinpoint Test HF .
Variable Camshaft Timing (VCT) System	GO to Pinpoint Test HK .
Accelerator Pedal Position Sensor	GO to Pinpoint Test DK .
Base Engine	REFER to the appropriate ENGINE article .
Automatic Transmission	REFER to the appropriate AUTOMATIC TRANSMISSION article .
Brake System Drag or Binding	REFER to the BRAKE SYSTEM - GENERAL INFORMATION .
Supercharger Bypass System	GO to Pinpoint Test KJ .
Additional Testing	GO to Pinpoint Test Z .
Additional Checks: Some vehicles have a TQ_CNTL PID available. Check this PID to determine if the PCM is reducing torque, and if so, why the torque is being reduced. As a PID display example; 0 equals no torque reduction requested, 1 equals torque truncation, which cuts fuel to protect when line pressure falls to minimum limit, and 2 equals traction control event, which cuts fuel/spark for traction control. Customer driving habits Correct PCM vehicle identification (VID) block information. REFER to , FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY (EEPROM) . Intake manifold runner control (IMRC) linkage (if equipped) Clutch (M/T) Charging system Engine RPM/speed limiting functions of the PCM (look for incorrect high vehicle speed signal from ABS, VSS, or OSS)	Visual. REFER to the applicable service information article .