Circuit Description
When the vehicle is first started, the engine operates in an Open Loop operation, ignoring the oxygen sensor (O2S) signal and calculating the air/fuel ratio based on inputs from the engine coolant temperature (ECT), the throttle position (TP), and the manifold absolute pressure (MAP) sensors only. The powertrain control module (PCM) will begin by using the oxygen sensor (O2S) signal for controlling the fuel delivery, Closed Loop, when the following conditions are met:
| • | The engine has run a minimum amount of time based on ECT at engine start up. |
| • | The oxygen sensor (O2S 1) has a varying voltage output showing that the sensor is hot enough to operate properly. |
| • | The ECT has increased a minimum amount based on the ECT at engine start up. |
Conditions For Running The DTC
| • | DTCs P0105, P0107, P0108, P0117, P0118, P0122, P0123, P0125, P0128, P0131, P0132, P0133, P0134, P0171, P0172, P0201, P0202, P0203, P0204, P0300, P0301, P0302, P0303, P0304, P0325, P0336, P0440, P0442, P0446, P0452, P0453, P0502, P0601, P0602, P1133, P1441, or P1621 are not set. |
| • | The engine has been running more than 100 seconds. |
| • | The engine speed is between 1,200-3,400 RPM. |
| • | The throttle position (TP) angle is between 10-40 percent. |
| • | The ECT is greater than 60°C (140°F). |
| • | The above conditions have been met for 2 seconds. |
Conditions For Setting The DTC
The engine is not in Closed Loop for 5 seconds out of 12.5 seconds.
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Clear the MIL and the DTC with a scan tool. |
Diagnostic Aids
DTC P0130 or slow response is most likely caused by one of the following conditions:
| • | The fuel pressure--The system will go rich if fuel pressure is too high. The PCM can compensate for some increase, however, if the pressure becomes too high, DTC P0172 may set. Refer to Fuel System Diagnosis . |
| • | A leaking injector--A leaking or malfunctioning injector can cause the system to go rich. |
| • | The manifold absolute pressure (MAP) sensor--An output that causes the PCM to sense a higher than normal manifold pressure (low vacuum) can cause the system to go rich. Disconnecting the MAP sensor will allow the PCM to set a fixed value for the MAP sensor. Substitute a different MAP sensor if the rich condition is gone while the MAP sensor is disconnected. |
| • | The fuel pressure regulator--Test for a leaking fuel pressure regulator diaphragm by inspecting for the presence of liquid fuel in the vacuum line to the fuel pressure regulator. |
| • | The throttle position (TP) sensor--An intermittent TP sensor output can cause the system to go rich due to a false indication of the engine accelerating. |
| • | O2S 1 contamination--Inspect the O2S 1 for silicone contamination from fuel or the use of improper RTV sealant. The O2S 1 sensor may have a white powdery coating and produce a high but false voltage signal, indicating a rich exhaust. The PCM will then reduce the amount of fuel delivered to the engine, causing a severe surge or driveability problem. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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When the system is operating correctly the O2S voltage should toggle above and below the specified values.
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The specified value is what is measured on a correctly operating system.
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The specified value is what is measured on a correctly operating system.
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This vehicle is equipped with a PCM which utilizes an electrically erasable programmable read only memory (EEPROM). When the PCM is replaced, the new PCM must be programmed.
Step | Action | Values | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | ||||||||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |||||||
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Important: If any other DTCs are set, except the HO2S DTCs, refer to other DTCs first before proceeding with this table.
Does scan tool indicate O2S voltage varying outside the specified values? | 400-500 mV | Go to Step 3 | Go to Step 4 | |||||||
3 | Operate vehicle within Failure Records conditions. Does the scan tool indicate this DTC failed this ignition? | -- | Go to Step 4 | Go to Diagnostic Aids | ||||||
4 | Inspect and test for the following:
Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 5 | ||||||
Does the voltage measure within the specified value? | 351-551 mV | Go to Step 6 | Go to Step 8 | |||||||
Does the scan tool indicate O2S voltage at or near the specified value? | 0 mV | Go to Step 9 | Go to Step 7 | |||||||
7 | Test the low signal circuit for an open or high resistance or for short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 11 | ||||||
8 | Test the high signal circuit for an open or high resistance or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 11 | ||||||
9 | Test for poor connections at the O2S. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 10 | ||||||
10 |
Important: Determine the cause of contamination before replacing the sensor. Inspect and test for the following:
Replace the O2S sensor. Refer to Oxygen Sensor Replacement . Did you complete the replacement? | -- | Go to Step 13 | -- | ||||||
11 | Test for poor connections at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 12 | ||||||
Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | -- | Go to Step 13 | -- | |||||||
13 |
Does the DTC run and pass? | -- | Go to Step 14 | Go to Step 2 | ||||||
14 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK | |||||||
