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 (KS), a lack of power may result when the vehicle is operated with a breakout box installed at the PCM. The KS circuits are not shielded in a breakout box, and KS signal noise may be noticed by the PCM. If this happens, spark timing is retarded and a lack of power may result.

NOTE: For applications with a KS, a lack of power may result if the engine has developed an abnormal noise. The KS may interpret some abnormal noise as detonation and retard spark timing.

SYSTEM/COMPONENT	REFERENCE ( PINPOINT TESTS unless noted)
Automatic Transmission Fluid	Visual.
Air Cleaner Element	Visual.
Check the following PIDS: LONGFT1/LONGFT2 (value between -20 and +20%) IMTV_F (if equipped): For both ignition ON, engine OFF and ignition ON, engine running with the transmission in PARK/NEUTRAL and the engine RPM greater than 3, 000 RPM, the PID should indicate NO FAULT in both situations.	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. IMTV_F 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 .
Mass Airflow (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 (APP) Sensor	GO to PINPOINT TEST DK .
Base Engine	REFER to the appropriate Engine System - General Information article and CARRY OUT the Inspection and Verification to continue diagnosis.
Automatic Transmission	REFER to the appropriate Automatic Transaxle/Transmission article, Shift Point Road Test to continue diagnosis.
Brake System Drag or Binding	REFER to the appropriate Brake System - General Information.
Supercharger Bypass System	GO to PINPOINT TEST KJ .
Turbocharger System	GO to PINPOINT TEST HN .
Additional Testing	GO to PINPOINT TEST Z .
Additional Checks: Some vehicles have a TQ_CNTRL PID available. Check this PID to determine if the PCM is reducing torque. The TQ_CNTRL PID may indicate which component or system, if any, is requesting a torque reduction. Customer driving habits Correct PCM vehicle identification (VID) block information. Refer to FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY (EEPROM) to carry out the Making Changes to the VID Block procedure. Clutch (M/T) Charging system Engine RPM or speed limiting functions of the PCM (look for incorrect high vehicle speed signal from ABS, VSS, or OSS)	Visual. REFER to appropriate Service Information article .
Brake Over Accelerator	CHECK for simultaneous brake pedal and accelerator pedal operation inadvertently activating the brake over accelerator feature. CHECK the BRKOVR_ACTION, BRKOVRD_POSS, and DIST_BRKOVRD PIDs for recent simultaneous brake pedal and accelerator pedal operation. ADVISE the customer that simultaneous brake pedal and accelerator pedal operation by the vehicle operator activates the brake over accelerator feature. REFER to POWERTRAIN CONTROL SOFTWARE for additional information.