Circuit Description
The Powertrain Control Module (PCM) supplies a voltage of approximately 0.45 volt between the oxygen sensor (O2S 1) signal and the ground circuit. The oxygen sensor (O2S 1) varies the voltage within a range of approximately 1 volt if the exhaust is rich, to approximately 0.10 volt if the exhaust is lean.
The sensor is like an open circuit and produces no voltage when below 315°C (600°F). An open sensor circuit or a cold sensor causes an Open Loop operation.
Replace the entire oxygen sensor (O2S 1) assembly. Do not attempt to repair the oxygen sensor if the following conditions exist:
| • | Damaged wiring |
| • | Damaged electrical connectors |
| • | Damaged terminals |
Conditions For Running The DTC
| • | DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0200, P0300, P0301, P0302, P0303, P0304, P0335, P0440.P0442, P0446, P0506, P0507, P0601, P0602, or P1441 are not set. |
| • | The air flow is more than 3 grams per second. |
| • | The engine coolant temperature (ECT) is more than 70°C (158°F). |
| • | The throttle position (TP) angle is between 4 percent and 56 percent for 20 seconds. |
| • | The engine run time is more than 30 seconds. |
Conditions For Setting The DTC
O2S 1 voltage is between 399 mV and 499 mV for 125 seconds.
Action Taken When the DTC Sets
| • | The malfunction indicator lamp (MIL) will illuminate after two consecutive ignition cycles in which the diagnostic runs with the fault active. |
| • | The PCM will record the operating conditions at the time that the diagnostic fails. This information will store in the Freeze Frame and Failure Records buffers. |
| • | A history DTC stores. |
| • | The coolant fan turns ON. |
| • | The vehicle will operate in an Open Loop operation. |
Conditions for Clearing the MIL/DTC
| • | The MIL will turn OFF after three consecutive ignition cycles in which the diagnostic runs without a fault. |
| • | A history DTC will clear after 40 consecutive warm-up cycles without a fault. |
| • | The MIL/DTCs can be cleared by using the scan tool. |
Diagnostic Aids
The normal scan tool voltage varies between 150 mV to 850 mV (0.15 volt to 0.85 volt) while in a Closed Loop operation.
An intermittent could be the result of the following conditions:
| • | A poor electrical connection |
| • | Rubbed-through wire insulation |
| • | A broken wire inside the insulation |
Check for a poor electrical connection or a damaged harness. Inspect the harness electrical connectors for the following conditions:
| • | Improper mating |
| • | Broken locks |
| • | Improperly formed electrical connectors |
| • | Damaged terminals |
| • | A poor terminal-to-wire connection |
| • | A damaged harness |
Replace the entire oxygen sensor (O2S 1) assembly. Do not attempt to repair the oxygen sensor if the following conditions exist:
| • | Damaged wiring |
| • | Damaged electrical connectors |
| • | Damaged terminals |
Test Description
The number(s) below refer(s) to the step number(s) on the Diagnostic Table.
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The Powertrain OBD System Check prompts you to complete some of the basic checks and to store the freeze frame and failure records data on the scan tool if applicable. This creates an electronic copy of the data taken when the malfunction occurred. The scan tool stores this data for later reference.
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During the engine warm-up, the O2S 1 should warm-up and the voltage output should vary between 150 mV and 850 mV. When the O2S 1 voltage varies, the engine will go into a Closed Loop operation. This step determines if the O2S 1 sensor is operating properly.
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This step will determine if the O2S 1 sensor is malfunctioning, or if the wiring or the PCM is the cause of the DTC P0134.
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Use only a high impedance digital volt ohmmeter for this test. This test checks the continuity of O2S 1 sensor signal circuit and the O2S 1 sensor low circuit; if the O2S 1 sensor low circuit is open, and if the PCM voltage on the O2S 1 sensor signal circuit will be over 0.6 volt (600 mV).
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Reprogram the replacement PCM and perform the crankshaft position system variation learn procedure. Refer to the latest Techline information for PCM programming and the Crankshaft Position System Variation Learn for the crankshaft position system variation learn procedure.
Step | Action | Value(s) | Yes | No | ||||
|---|---|---|---|---|---|---|---|---|
Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | |||||||
Does the scan tool indicate a Closed Loop operation? | 80°C (176°F) 1,200 RPM | |||||||
3 |
Does the scan tool indicate a Closed Loop operation? | -- | ||||||
Caution: Avoid contact with moving parts and hot surfaces while working around a running engine in order to prevent physical injury. Is the O2S 1 voltage below the specified value? | 50 mV (0.05 V) | |||||||
5 |
Was a repair necessary? | -- | ||||||
Does the O2S 1 voltage measure above the specified value? | 600 mV (0.6 V) | |||||||
7 | Does the O2S 1 voltage measure below the specified value? | 300 mV (0.3 V) | ||||||
Is the action complete? | -- | -- | ||||||
9 |
Caution: Avoid contact with moving parts and hot surfaces while working around a running engine in order to prevent physical injury. Replace the O2S 1 sensor. Refer to the Oxygen Sensor Replacement . Is the action complete? | -- | -- | |||||
10 |
Was a repair necessary? | -- | ||||||
11 |
Was a repair necessary? | -- | ||||||
12 |
Does the scan tool indicate that this diagnostic has ran and passed? | -- | ||||||
13 | Check to see if any additional DTCs are set. Does the scan tool display any DTCs that you have not diagnosed? | -- | Go to applicable DTC table | System OK |
