DTC P0068 or P1101
Diagnostic InstructionsDTC Descriptor
DTC P0068

Throttle Body Air Flow Performance

DTC P1101

Intake Air Flow System Performance

Circuit/System Description

Component

Description

B65 Intake Manifold Pressure and Air Temperature Sensor

The assembly has several functions:

Pressure

The signal voltage increases when the pressure increases.

Temperature

The temperature sensor is a negative temperature coefficient thermistor, a resistor which changes based on temperature.

  • Low temperature produces a high resistance:2.5 kΩ@20°C (68°F)
  • High temperature produces a low resistance:185 Ω@100°C (212°F)

The intake air temperature sensor 3 and the intake manifold pressure sensor are integrated in the same housing, which is located behind the throttle body.The sensor measures the temperature and pressure in the intake manifold between the throttle valve and the intake valves.

B75C Multifunction Intake Air Sensor

The assembly has several functions:

  • The mass air flow sensor is a hot film type sensor that measures the mass of air (not the volume) entering the engine. The signal varies with engine load and is displayed by the scan tool in Hertz (Hz) and grams per second (g/s).
  • The intake air humidity sensor uses the same signal circuit as the intake air temperature sensor 2. The intake air humidity sensor modulates the pulse width of the signal. The intake air temperature sensor 2 modulates the frequency of the signal. That means the signal is both, PWM and FM modulated.
  • The barometric pressure sensor generates an analog voltage that is proportional to the ambient air pressure.
  • The intake air temperature sensor 1 varies its resistance depending on the temperature.

B111 Turbocharger Boost Sensor

The sensor is a capacitive pressure transducer. Electronics in the sensor convert pressure into an analog voltage signal.

K20 Engine Control Module

The control module contains a microprocessor used to process input data to control outputs.

Q38 Throttle Body

The throttle valve is actuated by a bidirectional DC motor. A spring pulls the valve to a rest or default position, in which the valve is almost closed. The throttle actuator motor can push against the force of the spring to open or close the valve. The more current flow through the motor, the more the valve moves.

The component contains a contactless inductive position sensor. A fixed transmitter coil excites a movable rotor, which in turn induces a current in a fixed receiver coil. The current varies with the angle of the rotor. Electronics inside the sensor convert the current into digital data which is transmitted via a serial data circuit to the control module.

The control module compares the measured mass air flow with the calculated air flow based on throttle position and the calculated air flow based on manifold absolute pressure.

This DTC sets when the control module detects an inconsistency between the pressure sensors and cannot identify which sensor failed.

Conditions for Running the DTCP0068
  • Engine Speed=Greater than 800 RPM
  • Ignition Voltage=Greater than 6.4 V

Frequency the DTC runs=Continuously—After the running conditions are met—For greater than 1 s

P1101
  • DTC P0097, P0098, P0099, P0102, P0103, P0107, P0111, P0112, P0113, P0116, P0117, P0118, P0335, P0336 = Not set
  • Engine Speed=400 to 6,000 RPM
  • ECT Sensor=−7 to +130°C (+19 to +266°F)
  • IAT Sensor 1=−20 to +125°C (−4 to +257°F)

Frequency the DTC runs=Continuously—After the running conditions are met—For greater than 1 s

Conditions for Setting the DTCP0068

MAF Sensor&Calculated Air Flow=Not within a calibrated range

P1101

MAP Sensor&Calculated Air Flow=Not within a calibrated range

Actions Taken When the DTC Sets

DTCs listed in the DTC Descriptor category=Type A DTC—Exceptions listed below

DTC P1101=Type B DTC

Conditions for Clearing the DTC

DTCs listed in the DTC Descriptor category=Type A DTC—Exceptions listed below

DTC P1101=Type B DTC

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Master Electrical Component List

Electrical Information ReferenceDTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Special Tools
  • GE-52250 - Variable Pressure Leak Detector

Circuit/System Verification

  1. Ignition » On / Vehicle » In Service Mode
  2. Verify there are no DTCs set related to the following component/system:
    • 5V Reference Circuit
    • B65 Manifold Absolute Pressure and Intake Air Temperature Sensor—Circuit DTCs
    • B75 Mass Air Flow Sensor—Circuit DTCs
    • B111 Turbocharger Boost Sensor—Circuit DTCs
    • Q38 Throttle Body—Circuit DTCs@Throttle Position Sensor
    • If none of the DTCs are set
  3. Verify the scan tool parameter:Throttle Body Idle Air Flow Compensation=Less than 90%
    • If less than 90%
  4. Perform the scan tool control function:Throttle Sweep»Start

    Verify the scan tool parameter:Throttle Position Sensors 1 and 2=Agree

    • If the specified state
  5. Verify the scan tool parameter:
    • If not in the specified range
    • If in the specified range
  6. Perform the following procedure/test:Component/System Leak Test

    Verify the procedure/test passes.

    • If the procedure/test does not pass

      Repair or replace as necessary

    • If the procedure/test passes
  7. Verify the following conditions do not exist:
    • B65 Manifold Absolute Pressure and Intake Air Temperature Sensor—Visible Damage
    • B75C Multifunction Intake Air Sensor—Contamination of the measuring element/Visible Damage/Water intrusion
    • B111 Turbocharger/Supercharger Boost Pressure Sensor
      • Ice/Moisture/Restricted
      • Skewed
    • Q38 Throttle Body
      • Coking/Visible Damage
      • Ice/Moisture/Restricted
    • Q40 Turbocharger Bypass Valve Solenoid—Binding or Sticking/Loose/Visible Damage
    • Q42 Turbocharger Wastegate Solenoid Valve—Linkage@Turbocharger Wastegate Actuator—Binding or Sticking/Loose/Visible Damage
    • Air Cleaner Element—Dirty/Restricted
    • Catalytic Converter&Exhaust System—Blocked/Restricted/Visible Damage»Refer to:Symptoms - Engine Exhaust
    • Charge Air Cooler—Ice/Moisture/Restricted
    • Intake Air Duct—Collapsed/Restricted/Visible Damage
    • Intake Manifold—Restricted/Visible Damage
    • Positive Crankcase Ventilation SystemIce/Moisture/Restricted
    • If a condition exists

      Repair or replace as necessary

    • If no condition exists
  8. Verify the following conditions do not exist:Engine—Mechanical Condition»Refer to:Symptoms - Engine Mechanical

    For example:

    • Compressor Air Intake TurbochargerorTurbine Shaft Seal—Leaking—Engine Oil
    • Compressor Air Intake Turbocharger—Low oil pressure
    • Compressor Air Intake Turbocharger—Mechanical Condition/Worn
    • Exhaust ValveorIntake Valve—Stuck Open/Visible Damage
    • Exhaust Valve SeatorIntake Valve Seat—Visible Damage
    • Camshaft Lobe(s)—Visible Damage/Worn
    • Piston—Cracked/Visible Damage
    • Piston Ring—Seized/Visible Damage/Worn
    • If a condition exists

      Repair or replace as necessary

    • If no condition exists
  9. Engine » Idling — At normal operating temperature
  10. Verify the scan tool parameter:
    • MAP Sensor=26 to 52 kPa (3.8 to 7.5 PSI)@Idle Speed
    • MAP Sensor=The value should change with accelerator pedal input.
    • If between 26 and 52 kPa (3.8 and 7.5 PSI) and changes
  11. Verify the scan tool parameter:Boost Pressure Sensor=The value should change with accelerator pedal input.
    • If the value changes
  12. Increase the engine speed slowly to 3k RPM and then back to idle.
  13. Perform the scan tool function:Review Stored Data
  14. Observe the scan tool parameter frame by frame with a scan tool:MAF Sensor

    Verify the parameter changes smoothly and gradually in the recorded data as the engine speed was increased and decreased.

    • If the value does not change smoothly and gradually

      Refer to:DTC P0101

    • If the value changes smoothly and gradually
  15. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

    Verify the DTC does not set.

    • If the DTC sets

      Repeat the procedure starting at step 2

    • If the DTC is not set
  16. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair:Diagnostic Repair Verification