OBDII Trouble Codes

All 1996 and later 6.5L vehicles utilize the OBDII protocol which will require an OBDII scanner to query codes from the DLC under the steering column.

Note: Some cheap scanners show the correct code but the wrong description. Always refer to this list for the correct definition pertaining to the 6.5L platform

Diagnostic Trouble Code = DTC

P0101 Mass Air Flow (MAF) System Performance

P0102 MAF Sensor Circuit Low Frequency 

P0103 MAF Sensor Circuit High Frequency

P0112 Intake Air Temperature (IAT) Sensor Circuit Low Voltage 

P0113 IAT Sensor Circuit High Voltage

P0117 Engine Coolant Temperature (ECT) Sensor Circuit Low Voltage 

P0118 ECT Sensor Circuit High Voltage 

P0123 Accelerator Pedal Position (APP) Sensor 1 Circuit Performance 

P0122 APP Sensor 1 Circuit Low Voltage 

P0123 APP Sensor 1 Circuit High Voltage

P0126 Insufficient ECT for Stable Operation 

P0182 Fuel Temperature Sensor Circuit Low Voltage 

P0183 Fuel Temperature Sensor Circuit High Voltage 

P0215 Engine ShutOff Control Circuit 

P0216 Injection Timing Control Circuit

P0219 Engine Overspeed Condition 

P0220 APP Sensor 2 Circuit (TPS)

P0221 APP Sensor 2 Circuit Performance (TPS)

P0222 APP Sensor 2 Circuit Low Voltage (TPS)

P0223 APP Sensor 2 Circuit High Voltage (TPS)

P0225 APP Sensor 3 Circuit(TPS)

P0226 APP Sensor 3 Circuit Performance (TPS)

P0227 APP Sensor 3 Circuit Low Voltage (TPS)

P0228 APP Sensor 3 Circuit High Voltage (TPS)

P0231 Fuel Pump Feedback Circuit Low Voltage

P0236 Turbocharger Boost System

P0237 Turbo Boost Sensor Circuit Low Voltage

P0238 Turbo Boost Sensor Circuit High Voltage

P0251 Injection Pump Cam System (Optic sensor/Fuel metering fault)

P0263 Cylinder 1 Balance 

P0266 Cylinder 2 Balance 

P0269 Cylinder 3 Balance 

P0272 Cylinder 4 Balance 

P0275 Cylinder 5 Balance 

P0278 Cylinder 6 Balance 

P0281 Cylinder 7 Balance 

P0284 Cylinder 8 Balance 

P0300 Engine Misfire Detected

P0301 Cylinder 1 Misfire Detected

P0302 Cylinder 2 Misfire Detected

P0303 Cylinder 3 Misfire Detected

P0304 Cylinder 4 Misfire Detected

P0305 Cylinder 5 Misfire Detected

P0306 Cylinder 6 Misfire Detected

P0307 Cylinder 7 Misfire Detected

P0308 Cylinder 8 Misfire Detected

P0335 Crankshaft Position (CKP) Sensor Circuit

P0370 Timing Reference High Resolution

P0380 Glow Plug Circuit Performance

P0400 Exhaust Gas Recirculation (EGR) Flow Malfunction

P0401 EGR Flow Insufficient

P0402 EGR Flow Excessive

P0404 EGR System Performance

P0405 EGR Sensor Circuit Low Voltage

P0406 EGR Sensor Circuit High Voltage

P0501 Vehicle Speed Sensor Circuit (VSS)

P0567 Cruise Resume Circuit

P0568 Cruise Set Circuit

P0571 Cruise Brake Switch Circuit

P0601 Internal Control Module Memory

P0602 Control Module Programming

P0604 Control Module RAM Check Sum

P0606 PCM Internal Communications Interrupted

PO724 Brake Switch Circuit - High Input (TCC brake switch stuck on)

P1125 Accelerator Pedal Position System

P1191 Intake Air Duct Leak

P1214 Injection Pump Timing Offset (Pump needs rotated and TDCO procedure performed)

P1216 Fuel Solenoid Response Time Short

P1217 Fuel Solenoid Response Time Long

P1218 Injection Pump Calibration Circuit

P1406 EGR Valve Position

P1409 EGR Vacuum System Leak

P1621 EEPROM Write Failure

P1626 Vehicle Theft Deterrent (VTD) Controller Serial Data Circuit

P1627 A/D Performance

P1630 Theft Deterrent PCM in Learn Mode

P1631 Theft Deterrent Password Incorrect

P1635 5 Volt Reference Low

P1641 Malfunction Indicator Lamp (MIL) Control Circuit

P1643 Wait To Start Lamp Control Circuit

P1653 EGR Vent Solenoid Control Circuit

P1654 Service Throttle Soon Lamp Control Circuit

P1655 EGR Solenoid Control Circuit

P1656 Wastegate Solenoid Control Circuit

U1026 Loss of Class 2 Communication

This is the most common issue that arises on the 1996 and later trucks. Either from a failing component of the vacuum controlled wastegate system or if you have put on a mechanical wastegate and vacuum pump delete but still have the stock tune that can not cope with it.

If you contact us about an issue with the following and you have a vacuum pump delete but are on the stock tune, we will tell you to get a tune:

P0236 Turbocharger Boost System (Measured boost differs from expected. Either too high or too low)

P0237 Turbo Boost Sensor Circuit Low Voltage

P0238 Turbo Boost Sensor Circuit High Voltage

P1656 Wastegate Solenoid Control Circuit (WGS. The vacuum control solenoid above the US driver side valve cover)

See Attached