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Makes 🢒 GMC_Truck 🢒 1999 🢒 GMC P42 Commercial Chassis 🢒 Transmission/Transaxle 🢒 Automatic Transmission - 4L80-E 🢒 Diagnostic Trouble Code Identification

Diagnostic Trouble Code Identification for GMC Truck GMC P42 Commercial Chassis 1999

Diagnostic Trouble Code Identification Gas

Diagnostic Trouble Code (DTC) Identification Diagnostic Types

DTC

Description

DTC Type*

Default Action

P0218

Transmission Fluid Overtemperature

D

The VCM freezes shift adapts.

P0502

Vehicle Speed Sensor Circuit -- Low Input

D/B
    • The VCM illuminates the MIL for California emissions.
    • The VCM freezes shift adapts.
    • The VCM commands maximum line pressure
    • The VCM defaults a calculated OSS from the A/T ISS sensor output.

P0503

Vehicle Speed Sensor Circuit -- Intermittent

D/B
    • The VCM illuminates the MIL for California emissions.
    • The VCM freezes shift adapts.
    • The VCM commands maximum line pressure.
    • The VCM defaults a calculated OSS from the A/T ISS sensor output.

P0560

System Voltage Malfunction

D
    • The VCM commands an immediate landing to second gear.
    • The VCM freezes shift adapts.
    • The VCM turns off all transmission output devices.

P0711

Automatic Transmission Fluid Temperature (TFT) Sensor Circuit Range/Performance

D
    • The VCM freezes shift adapts.
    • Default line pressure.
    • The VCM calculates a default transmission fluid temperature based on engine coolant temperature, intake air temperature and engine run time.

P0712

Transmission Fluid Temperature Sensor Circuit -- Low Input

D
    • The VCM freezes shift adapts.
    • Default line pressure.
    • The VCM calculates a default transmission fluid temperature based on engine coolant temperature, intake air temperature and engine run time.

P0713

Transmission Fluid Temperature Sensor Circuit -- High Input

D
    • The VCM freezes shift adapts.
    • Default line pressure.
    • The VCM calculates a default transmission fluid temperature based on engine coolant temperature, intake air temperature and engine run time.

P0716

Input Speed Sensor Circuit -- Intermittent

D/B
    • The VCM illuminates the MIL for California emissions.
    • The VCM freezes shift adapts.
    • The VCM commands maximum line pressure.

P0717

Input Speed Sensor Circuit -- Low Input

D/B
    • The VCM illuminates the MIL for California emissions.
    • The VCM freezes shift adapts.
    • The VCM commands maximum line pressure.

P0719

Brake Switch Circuit -- Low Input

D

--

P0724

Brake Switch Circuit -- High Input

D

--

P0730

Incorrect Gear Ratio

D
    • The VCM commands maximum line pressure.
    • The VCM freezes shift adapts.

P0741

Torque Converter Clutch System Stuck Off

D/B
    • The VCM illuminates the MIL for California emissions.
    • Default line pressure.
    • The VCM inhibits TCC engagement.
    • The VCM inhibits fourth gear engagement.

P0742

Torque Converter Clutch System Stuck On

D/B
    • The VCM illuminates the MIL for California emissions.
    • The VCM commands maximum line pressure.
    • The VCM freezes shift adapts.

P0748

Pressure Control Circuit -- Electrical

D
    • The VCM disables the PC Solenoid valve.
    • The VCM freezes shift adapts.

P0751

1-2 Shift Solenoid Valve -- Performance

D/B
    • The VCM illuminates the MIL for California emissions.
    • The VCM commands maximum line pressure.
    • The VCM freezes shift adapts.
    • 3-2 downshifts above 25 MPH are inhibited.

P0753

1-2 Shift Solenoid Valve Circuit -- Electrical

D/A
    • The VCM illuminates the MIL for California emissions.
    • The VCM freezes shift adapts.
    • 3-2 downshifts above 25 MPH are inhibited.
    • The VCM commands maximum line pressure.

P0756

2-3 Shift Solenoid Valve -- Performance

D/A
    • The VCM illuminates the MIL for California emissions.
    • The VCM commands an immediate landing to second gear.
    • The VCM freezes shift adapts.
    • The VCM commands maximum line pressure.

P0758

2-3 Shift Solenoid Valve Circuit-- Electrical

D/A
    • The VCM illuminates the MIL for California emissions.
    • The VCM commands maximum line pressure.
    • The VCM freezes shift adapts.
    • The VCM commands an immediate landing to second gear.

P1810

Automatic Transmission Fluid Pressure Manual Valve Position Switch Circuit Malfunction

D/B
    • The VCM illuminates the MIL for California emissions.
    • The VCM freezes shift adapts.
    • The VCM assumes D4 shift pattern.
    • The VCM commands maximum line pressure.
    • The VCM forces TCC apply when fourth gear is commanded.

P1860

Torque Converter Clutch Pulse Width Modulation Solenoid Valve Circuit-Electrical

D/A
    • The VCM illuminates the MIL for California emissions.
    • The VCM inhibit s TCC engagement.
    • The VCM inhibits fourth gear engagement.
    • The VCM freezes shift adapts.

P1870

Transmission Component Slipping

D/B
    • The VCM illuminates the MIL for California emissions.
    • The VCM commands maximum line pressure.
    • The VCM inhibits TCC engagement.
    • The VCM inhibits fourth gear engagement.
    • The VCM freezes shift adapts.

P1875

Four-Wheel Drive Low Switch Circuit Electrical

D/B
    • The VCM illuminates the MIL for California emissions.
    • The VCM freezes shift adapts.
    • The VCM assumes a 4WD Lo state if the switch fails when open, or the VCM assumes a 4WD High state if the switch fails when closed, for a transmission shift pattern.
    • The VCM inhibits fourth gear engagement.
    • The VCM freezes shift adapts.

*DTC Types:

A--Emission related, will turn on the MIL after the first failure.

B--Emission related, will turn on the MIL after two consecutive trips with a failure.

C--Non-emission related, will turn on the service lamp after the first failure.

D--Non-emission related, no lamps.

Diagnostic Trouble Code Identification L57/L65 EFI

Diagnostic Trouble Code (DTC) Identification Diagnostic Types

DTC

Description

DTC Type*

Default Action

P0218

Transmission Fluid Overtemperature

D

The PCM freezes shift adapts.

P0560

System Voltage Malfunction

D
    • The PCM inhibits TCC engagement.
    • The PCM freezes shift adapts.
    • The PCM turns off the PC solenoid valve.
    • The PCM commands an immediate landing into 2nd gear.

P0711

Transmission Fluid Temperature Sensor Circuit Range/Performance

D
    • The PCM freezes shift adapts.
    • Default line pressure.
    • The PCM calculates a default transmission fluid temperature based on engine coolant temperature, intake air temperature and engine run time.

P0712

Transmission Fluid Temperature Sensor Circuit -- Low Input

D
    • The PCM freezes shift adapts.
    • Default line pressure.
    • The PCM calculates a default transmission fluid temperature based on engine coolant temperature, intake air temperature and engine run time.

P0713

Transmission Fluid Temperature Sensor Circuit -- High Input

D
    • The PCM freezes shift adapts.
    • Default line pressure.
    • The PCM calculates a default transmission fluid temperature based on engine coolant temperature, intake air temperature and engine run time.

P0716

Input Speed Sensor Circuit -- Intermittent

B
    • The PCM illuminates the MIL.
    • The PCM freezes shift adapts.
    • The PCM commands maximum line pressure.

P0717

Input Speed Sensor Circuit -- Low Input

B
    • The PCM illuminates the MIL.
    • The PCM freezes shift adapts.
    • The PCM commands maximum line pressure.

P0719

Brake Switch Circuit -- Low Input

D

--

P0722

Output Speed Sensor -- Low Input

B
    • The PCM illuminates the MIL.
    • The PCM freezes shift adapts.
    • The PCM commands maximum line pressure.
    • The PCM calculates OSS from ISS.

P0723

Output Speed Sensor Intermittent

B
    • The PCM illuminates the MIL.
    • The PCM freezes shift adapts.
    • The PCM commands maximum line pressure.
    • The PCM calculates OSS from ISS.

P0724

Brake Switch Circuit -- High Input

D

Apply TCC if APP is greater than 0.5% and the vehicle speed is greater than 30 mph.

P0730

Incorrect gear ratio

D
    • The PCM commands maximum line pressure.
    • The PCM freezes shift adapts.

P0741

Torque Converter Clutch System Stuck Off

B
    • The PCM illuminates the MIL.
    • The PCM inhibits TCC engagement.
    • The PCM inhibits fourth gear engagement.
    • The PCM commands increased line pressure.

P0742

Torque Converter Clutch System Stuck On

B
    • The PCM illuminates the MIL.
    • The PCM freezes shift adapts.
    • The PCM commands maximum line pressure.

P0748

Pressure Control Solenoid Circuit -- Electrical

D
    • The PCM freezes shift adapts.
    • The PCM commands maximum line pressure by disabling the PC solenoid valve.

P0751

1-2 Shift Solenoid Valve --Performance

B
    • The PCM illuminates the MIL.
    • The PCM freezes shift adapts.
    • The PCM commands maximum line pressure.

P0753

1-2 Shift Solenoid Valve -- Electrical

A
    • The PCM illuminates the MIL.
    • The PCM freezes shift adapts.
    • The PCM commands maximum line pressure.

P0756

2-3 Shift Solenoid Valve -- Performance

A
    • The PCM illuminates the MIL.
    • The PCM commands an immediate landing into second gear.
    • The PCM freezes shift adapts.
    • The PCM commands maximum line pressure.

P0758

2-3 Shift Solenoid Valve -- Electrical

A
    • The PCM illuminates the MIL.
    • The PCM commands an immediate landing to second gear.
    • The PCM freezes shift adapts.
    • The PCM commands maximum line pressure.

P1810

Transmission Fluid Pressure Manual Valve Position Switch Assembly -- Circuit Malfunction

B
    • The PCM illuminates the MIL.
    • The PCM freezes shift adapts.
    • The PCM assumes a D4 shift pattern.
    • The PCM commands maximum line pressure.
    • The PCM commands TCC apply with 4th gear commanded ON.

P1811

Maximum Adapt and Long Shift

D
    • The PCM freezes shift adapts.
    • The PCM commands maximum line pressure.

P1860

Torque Converter Clutch Pulse Width Modulation Solenoid Circuit -- Electrical

A
    • The PCM illuminates the MIL.
    • The PCM inhibits TCC engagement.
    • The PCM inhibits fourth gear engagement.
    • The PCM freezes shift adapts.

P1870

Transmission Component Slipping

B
    • The PCM illuminates the MIL.
    • The PCM commands maximum line pressure.
    • The PCM inhibits TCC engagement.
    • The PCM inhibits fourth gear engagement.
    • The PCM freezes shift adapts.

P1875

Four-Wheel Drive Low Switch Circuit -- Electrical

B
    • The PCM illuminates the MIL.
    • The PCM freezes shift adapts.
    • The PCM assumes a 4WD Lo state if the switch fails when open, or the PCM assumes a 4WD High state if the switch fails when closed, for a transmission shift pattern.
    • DTC P1875 is stored in PCM history.

DTC Types:

  • A--Emission related, will turn on the MIL after the first failure.
  • B--Emission related, will turn on the MIL after two consecutive trips with a failure.
  • C--Non-emission related, will turn on the service lamp after the first failure.
  • D--Non-emission related, no lamps.

Diagnostic Trouble Code Identification L57 MFI

Diagnostic Trouble Code (DTC) Identification Diagnostic Types

DTC

Description

Default Action

21

Throttle Position Sensor Circuit High Voltage
    • Set line pressure to maximum
    • Use 35% throttle as a default
    • Inhibit fourth gear if in Hot Mode

22

Throttle Position Sensor Circuit Low Voltage
    • Set line pressure to maximum
    • Use 35% throttle as a default
    • Inhibit fourth gear if in Hot Mode

24

Output Shaft Speed (OSS) Sensor Low
    • Set line pressure to maximum
    • Allow 4-3, 3-2, and 1-2 shifts, then maintain second gear
    • Calculate output speed from input speed

28

TFP Valve Position Switch
    • Assume Drive 4 is selected
    • Inhibit fourth gear if in Hot Mode
    • Inhibit TCC operation

37

TCC Brake Switch Low Input
    • No TCC
    • No fourth gear if in Hot Mode

38

TCC Brake Switch High Input
    • No TCC
    • No fourth gear if in Hot Mode

39

Torque Converter Clutch (TCC) Stuck OFF

Inhibit fourth gear if in Hot Mode

51

Prom Error

--

52

System Voltage High Long
    • Maximum line pressure
    • 2nd gear landing
    • Inhibit TCC

53

System Voltage High
    • Maximum line pressure
    • 2nd gear only
    • Inhibit TCC operation

58

Transmission Fluid Temperature (TFT) Sensor Circuit High
    • TCC in second, third, and fourth gears
    • Maximum line pressure
    • Defaults to 140°C TFT

59

Transmission Fluid Temperature (TFT) Sensor Circuit Low
    • TCC in second, third, and fourth gears
    • Maximum line pressure
    • Defaults to 140°C TFT

63

BARO Sensor Circuit High

No altitude compensation of shift patterns

64

BARO Sensor Circuit Low

No altitude compensation of shift patterns

68

Transmission Component Slipping
    • Inhibit TCC operation
    • Inhibit manual mode operation

69

Torque Converter Clutch (TCC) Stuck ON

--

71

Camshaft Position Sensor (CMP) Circuit Low (Engine Speed Sensor)

The TCM inhibits TCC

72

Transmission Output Shaft Speed (OSS) Sensor Circuit Loss
    • Maximum line pressure
    • Soft landing into second gear

73

Pressure Control (PC) Solenoid Valve Electrical

Maximum line pressure

74

Automatic Transmission Input Shaft Speed (A/T ISS) Sensor Circuit

The TCM inhibits TCC

75

System Voltage Low
    • Turn pressure control solenoid OFF
    • Allow 4-3, 3-2, and 1-2 shifts, then maintain second gear
    • Inhibit TCC and fourth gear

79

Transmission Fluid Overtemperature

--

81

2-3 Shift Solenoid (2-3 SS) Valve Circuit Fault
    • Inhibit TCC operation
    • Maximum line pressure

82

1-2 Shift Solenoid (1-2 SS) Valve Circuit Fault
    • Second and third gears only
    • Maximum line pressure

83

TCC PWM Solenoid Valve Circuit Fault
    • Inhibit fourth gear if in Hot Mode
    • Inhibit TCC operation

85

Undefined Gear Ratio
    • Maximum line pressure
    • Inhibit TCC

86

Low Ratio Error
    • Defaults to second gear
    • Maximum line pressure
    • Inhibits TCC

87

High Ratio Error
    • Landing to second gear
    • Maximum line pressure
    • Inhibits TCC