• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
The engine control module (ECM) uses the following information to calculate an expected airflow rate:
• | Throttle position (TP) |
• | Barometric pressure (BARO) |
• | Manifold absolute pressure (MAP) |
• | Intake air temperature (IAT) |
• | Engine speed |
• | Mass air flow (MAF) |
• | The engine is running and the engine speed is more than 800 RPM. |
• | DTC P0068 runs continuously when the above conditions are met. |
• | DTCs P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0122, P0123, P0128, P0220, P0221, P0222, P0223, P0335, P0336, P0401, P0405, P0601, P0602, P0603, P0604, P0606, P060D, P062F, P0652, P0653, P1404, P1516, P2101, P2119, P2135, P2176 are not set. |
• | The engine coolant temperature (ECT) is between 70-121°C (158-249°F). |
• | The engine IAT is at 0.7 to +60°C (+19 to +140°F). |
• | The engine speed is between 550-5,000 RPM. |
• | DTC P0121 runs continuously when the above conditions are met. |
The ECM detects that the throttle position and indicated engine load do not correspond with the expected load and throttle position for less than 1 second.
• | The ECM detects that the difference between the MAP sensor pressure value and expected value is greater than the specified value. |
• | The ECM detects that the difference between the MAF value and the desired value is greater than the specified value. |
• | DTC P0068 is a Type A DTC. |
• | DTC P0121 is a Type B DTC. |
• | The control module commands the TAC system to operate in Reduced Engine Power mode. |
• | The message center or the indicator displays Reduced Engine Power. |
• | DTC P0068 is a Type A DTC. |
• | DTC P0121 is a Type B DTC. |
Diagnostic Trouble Code (DTC) Type Definitions
• | A loose or damaged throttle blade |
• | A broken throttle shaft |
• | Any throttle body damage |
⇒ | If any of these conditions exists, replace the throttle body assembly. |
• | The vacuum hoses for splits, leaks and proper connection |
• | Air leaks at throttle body mounting area and intake manifold sealing surfaces |
⇒ | If a condition is found, repair as necessary. |
⇒ | If more than 4 volts or less than 0.8 volt, refer to DTC P0106. |
⇒ | If the MAP sensor kPa does not change, refer to DTC P0106. |
5.1. | Run the engine at idle speed. |
5.2. | Increase the engine speed slowly to 3,000 RPM, then return to idle. |
5.3. | The MAF sensor parameter should change smoothly and gradually as the engine speed is increased and returned to idle. The MAF sensor parameter should change smoothly and gradually as the engine speed is increased and returned to idle. |
⇒ | If the MAF sensor parameter doesn't change smoothly and gradually as the engine speed increases and returns to idle, refer to DTC P0101 or P1101. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for ECM replacement, setup, and programming |