Quote:
Originally Posted by bronco
Here I am again asking for help. Pulled some codes from '04 would like to know what they are or mean. Hope for help or someone to tell me whare to look them up. Have no GM dealer that I know well enough to ask.
P0101
P0172
P0175
U1000
Thanks,
bronco
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DTC P0101 (With Throttle Actuator Control)
Circuit Description
The mass air flow (MAF) sensor is an air flow meter that measures the amount of air entering the engine. The powertrain control module (PCM) uses the MAF sensor signal to provide the correct fuel delivery for all engine speeds and loads. A small quantity of air entering the engine indicates a deceleration or idle condition. A large quantity of air entering the engine indicates an acceleration or high load condition. The MAF sensor has the following circuits:
• An ignition 1 voltage circuit
• A ground circuit
• A signal circuit
The PCM applies a voltage to the sensor on the signal circuit. The sensor uses the voltage to produce a frequency based on the inlet air flow through the sensor bore. The frequency varies within a range of near 2,000 Hertz at idle to near 10,000 Hertz at maximum engine load. The PCM uses the following sensor inputs to calculate a predicted MAF value:
• The manifold absolute pressure (MAP) sensor
• The intake air temperature (IAT) sensor
• The engine coolant temperature (ECT) sensor
• The engine speed in revolutions per minute (RPM)
The PCM compares the actual MAF sensor frequency signal to the predicted MAF value. This comparison will determine if the signal is stuck based on a lack of variation, or is too low or too high for a given operating condition. If the PCM detects the actual MAF sensor frequency signal is not
DTC P0172 or P0175
Circuit Description
The powertrain control module (PCM) controls the air/fuel metering system in order to provide the best possible combination of driveability, fuel economy and emission control. Fuel delivery is controlled differently during Open and Closed Loop. During Open Loop the PCM determines fuel delivery based on sensor signals, without oxygen sensor input. During Closed Loop the PCM adds oxygen sensor inputs and level of purge to calculate Short and Long Term fuel trim adjustments. If the oxygen sensors indicate a lean condition, fuel trim values will be above 0 percent . If the oxygen sensors indicate a rich condition, fuel trim values will be below 0 percent. The values for the Short Term fuel trim change rapidly in response to the heated oxygen sensor (HO2S) voltage signals. Long Term fuel trim makes coarse adjustments in order to maintain an Air/Fuel Ratio of 14.7:1. A block of cells contain information arranged in combinations of engine RPM and engine load for a full range of vehicle operating conditions. The long term fuel trim diagnostic is based on an average of cells currently being used. The PCM selects the cells based on the engine speed and engine load. The fuel trim diagnostic will conduct a test to determine if a rich failure actually exists or if excessive vapor from the evaporative emission (EVAP) canister is causing a rich condition. If the PCM detects an excessively rich condition, DTC P0172 or P0175 sets.
Conditions for Running the DTC
• DTCs P0101, P0103, P0108, P0135, P0137, P0141, P0200, P0300, P0410, P0420, P0430, P0440, P0442, P0443, P0446, P0449, P0506, P0507 or P1441 are not set.
• The engine coolant temperature (ECT) is between 75-115°C (167-239°F).
• The intake air temperature (IAT) is between -20 to +90°C (+4 and +194°F).
• The manifold absolute pressure (MAP) is between 26-90 kPa (3.7-13 psi).
• The vehicle speed is less than 137 km/h (85 mph).
• The engine speed is between 400-3,000 RPM.
Linear Mode
