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| • | 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) 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 loop and closed loop. During open loop, the ECM determines fuel delivery based on sensor signals without heated oxygen sensor (HO2S) input. During closed loop, the ECM adds heated oxygen sensor (HO2S) inputs and level of purge to calculate the short and long term fuel trim adjustments. If the heated oxygen sensor (HO2S) indicates a lean condition, the fuel trim values will be above 0%. If the heated oxygen sensor (HO2S) indicates a rich condition, the fuel trim values will be below 0%. The short term fuel trim values change rapidly in response to the heated oxygen sensor (HO2S) voltage signals. The long term fuel trim makes rough adjustments in order to maintain an air/fuel ratio of 14.7:1.
The heating elements inside each heated oxygen sensor (HO2S) heat the sensor to bring the sensor up to operating conditions faster. This allows the system to enter closed loop earlier and the control module to calculate the air-to-fuel ratio sooner.
The HO2S utilises the following circuits:
| • | A signal circuit |
| • | A low reference circuit |
| • | An ignition voltage circuit |
| • | A heater control circuit |
| • | DTCsP0030 00, P0031 00, P0032 00, P0111 00, P0112 00, P0113 00, P0114 00, P0117 00, P0118 00, P0119 00, P0122 00, P0123 00, P0130 00, P0131 00, P0132 00, P0133 00, P0134 00, P0135 00, P0201 00, P0202 00, P0203 00, P0204 00, P0222 00, P0223 00, P0261 00, P0262 00, P0264 00, P0265 00, P0267 00, P0268 00, P0270 00, P0271 00, P0301 00, P0302 00, P0303 00, P0304 00, P0335 00, P0336 00, P0340 00, P0341 00, P0365 00, P0366 00, P0443 00, P0458 00, P0459 00, P0496 00, P2227 00, P2228 00, P2229 00, P2297 00, P2A00 00 are not set. |
| • | The loop status parameter indicates closed. |
| • | The engine coolant temperature (ECT) is between -38 to +150°C (-36.4 to +302°F). |
| • | The intake air temperature (IAT) is between -38 to +150°C (-36.4 to +302°F). |
| • | The manifold absolute pressure (MAP) is between 5-255 kPa (0.73-37 psi). |
| • | The engine speed is between 400-6 000 RPM. |
| • | The barometric pressure (BARO) is more than 70 kPa (10 PSI). |
| • | DTCs P0172 00 and P2097 00 run continuously when the above conditions have been met. |
| • | DTCsP000A 00, P000B 00, P0010 00, P0011 00, P0013 00, P0016 00, P0017 00, P0030 00, P0031 00, P0032 00, P0117 00, P0118 00, P0119 00, P0121 00, P0122 00, P0123 00, P0131 00, P0132 00, P0133 00, P0137 00, P0138 00, P0139 00, P0140 00, P0141 00, P0171 00, P0172 00, P0201 00, P0202 00, P0203 00, P0204 00, P0221 00, P0222 00, P0223 00, P0261 00, P0262 00, P0264 00, P0265 00, P0267 00, P0268 00, P0270 00, P0271 00, P0300 00, P0301 00, P0302 00, P0303 00, P0304 00, P0313 00, P0335 00, P0336 00, P0340 00, P0341 00, P0365 00, P0366 00, P0420 00, P0443 00, P0458 00, P0459 00, P2088 00, P2089 00, P2090 00, P2091 00, P2100 00, P2101 00, P2176 00, P2270 00, P2271 00, P2297 00, P2300 00, P2301 00, P2303 00, P2304 00, P2306 00, P2307 00, P2309 00, P2310 00, P2A00 00, P2A01 00 are not set. |
| • | The ignition is ON. |
| • | The evaporative emission (EVAP) system is not purging. |
| • | The post catalyst fuel trim is enabled. |
| • | This DTC P2097 00 runs continuously when the above conditions have been met. |
| • | The long term fuel trim weighted average value is more or less than a calibrated value. |
| • | The above condition is present for approximately 3 min after the conditions for running the DTC have been met. |
The long term fuel trim has reached its limit while the heated oxygen sensor (HO2S) voltage is still trying to move the adjustment further in the same direction.
DTCs P0172 00 and P2097 00 are Type B DTC.
DTCs P0172 00 and P2097 00 are Type B DTC.
| • | On vehicles equipped with a vacuum brake booster, rapid brake pedal cycling may imitate a vacuum leak. |
| • | A failed HO2S will not cause DTC P2097 00 to set without the occurrence of circuit related HO2S DTCs. Do not replace an HO2S to address this DTC. |
| • | An exhaust system leak that may not be audible can set these DTCs. |
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Control Module References for scan tool information
Note: Disregard any transmission symptoms, antilock brake system (ABS) indicators, and traction control system indicators until any fuel trim faults are repaired. A fuel trim fault may cause default actions such as harsh shifts and illumination of the ABS/traction control system indicators.
| ⇒ | If any DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle . |
| ⇒ | If the value does not vary from approximately 40 mV to approximately 900 mV, refer to DTC P0137-P0140, P2270, P2271, or P2A01 . |
Note: The EVAP purge enablement may cause the fuel trim to be momentarily outside the normal range.
Note: Allow the engine to reach operating temperature. With the engine running, observe the scan tool Long Term Fuel Trim parameter with a scan tool. The value should be less than approximately 18% with the engine running at operating temperature.
| ⇒ | If the value is not less than -25%, inspect for the following: |
| • | With the ignition ON and the engine OFF, observe the scan tool HO2S Sensor 1 parameter. The scan tool MAP Sensor pressure should be within the range specified for your altitude. Refer to Altitude Versus Barometric Pressure . |
| ⇒ | If the MAP sensor does not indicate the correct barometric pressure, refer to DTC P0106, P0107, or P0108 . |
| • | With the engine idling and the transmission in the park or neutral position, observe the scan tool MAP Sensor parameter. The scan tool MAP Sensor parameter should be between 19-42 kPa (2.8-6.1 PSI). |
| ⇒ | If the scan tool MAP Sensor parameter is not between 19-42 kPa (2.8-6.1 PSI), refer to DTC P0106, P0107, or P0108 . |
| • | Vacuum hoses for splits, kinks, and improper connections |
| • | The air inlet duct for being collapsed or restricted |
| • | The air filter for being dirty or restricted |
| • | Objects blocking the throttle body |
| • | Excessive fuel in the crankcase due to leaking fuel injectors |
| • | The evaporative emissions control system for improper operation |
| • | Excessive fuel pressure--Refer to Fuel System Diagnosis . |
| • | Malfunctioning fuel injectors--Refer to Fuel Injector Diagnosis : Scan Tool → Special Tool . |
| • | Fuel contamination--Refer to Alcohol/Contaminants-in-Fuel Diagnosis . |
| • | The HO2S for improper installation and for electrical wires or connectors that may have contacted the exhaust system |
| • | The B52A Heated Oxygen Sensor 1 sensor 1 signal circuit open, shorted to ground, or shorted to the low reference circuit |
| • | The B52A Heated Oxygen Sensor 1 sensor 1 low signal circuit for an open circuit or high resistance |
| • | Air Cleaner Assembly Replacement : LDE, LXV, LUW, 2H0 and LFH |
| • | Air Cleaner Element Replacement : 1.6L LDE, LXV, 1.8L 2H0, LUW and LFH |
| • | Heated Oxygen Sensor Replacement - Sensor 1 : LDE, LXV, LUW, 2H0 |
| • | Manifold Absolute Pressure Sensor Replacement : 1.8L 2H0 and LUW |
| • | Throttle Body Assembly Replacement : 1.6L LDE, LXV, 1.8L 2H0, and LUW |
Note: After repairs, use the scan tool fuel trim reset function in order to reset the long term fuel trim.
Note: Do not clear codes with the engine running. The codes may reset in the same ignition cycle.
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