Circuit Description
Heated oxygen sensors (HO2S) are used for fuel control and post catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content in the exhaust stream. The HO2S must reach operating temperature to provide an accurate voltage signal. Heating elements inside the HO2S minimize the time required for the sensors to reach operating temperature. The engine control module (ECM) supplies the HO2S with a reference, or bias, voltage of about 450 mV. When the engine is first started the ECM operates in Open Loop, ignoring the HO2S voltage signal. Once the HO2S reaches operating temperatures and Closed Loop is achieved, the HO2S generates a voltage within a range of 0-1,000 mV that fluctuates above and below bias voltage. High HO2S voltage indicates a rich exhaust stream. Low HO2S voltage indicates a lean exhaust stream.
If the ECM detects the loop status is open too long, DTC P0130 will set.
Conditions for Running the DTC
| • | DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0128, P0131, P0132, P0133, P0134, P0171, P0172, P0201, P0202, P0203, P0204, P0300-P0304, P0336, P0440, P0442, P0446, P0452, P0453, P0506, P0507, P0601, P0602, P0604, P0606, P1120, P1133, P1134, P1220, P1221, P1271, P1275, P1280, P1441, P1512, P1514, P1515, P1516, P1621, P1635, P1639, P1680, P1681 are not set. |
| • | The Engine Run Time parameter is more than 140 seconds. |
| • | The Engine Speed parameter is between 1,200-3,400 RPM. |
| • | The TP Angle parameter is between 10-40 percent. |
| • | The ECT Sensor parameter is more than 65°C (149°F). |
| • | The APP Angle parameter is more than 1.2 percent. |
| • | The above conditions are met for 2 seconds. |
Conditions for Setting the DTC
The ECM detects that the Loop Status parameter is open for 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. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
An HO2S heater fault may set this DTC.
-
If the voltage is varying above and below the specified value, the condition is not present.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Engine Control Module Connector End Views | ||||||||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |||||||
Is the HO2S 1 heater current parameter within the specified range? | 0.217-1.56 A | Go to Step 3 | Go to DTC P0135 or P0141 | |||||||
Is the HO2S 1 voltage parameter varying above and below the specified range? | 300-600 mV | Go to Step 4 | Go to Step 5 | |||||||
4 |
Did the DTC fail this ignition? | -- | Go to Step 5 | Go to Intermittent Conditions | ||||||
5 |
Is the HO2S 1 voltage parameter more than the specified value? | 800 mV | Go to Step 6 | Go to Step 7 | ||||||
6 |
Important: The normal voltage on the high signal circuit is between 400-500 mV. Important: The sensor may be damaged if the circuit is shorted to a voltage source. Test the HO2S 1 high signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 18 | Go to Step 17 | ||||||
7 |
Is the HO2S 1 voltage parameter within the specified range? | 400-500 mV | Go to Step 9 | Go to Step 8 | ||||||
8 |
Did you find and correct the condition? | -- | Go to Step 18 | Go to Step 14 | ||||||
9 |
Is the HO2S 1 voltage parameter within the specified range? | 400-500 mV | Go to Step 11 | Go to Step 10 | ||||||
10 |
Did you find and correct the condition? | -- | Go to Step 18 | Go to Step 15 | ||||||
11 | Measure the voltage from the high signal circuit of the HO2S 1 harness connector on the engine harness side to a good ground with a DMM. Refer to Circuit Testing in Wiring Systems. Is the voltage more than the specified value? | 1.0 V | Go to Step 12 | Go to Step 13 | ||||||
12 |
Important: The normal voltage on the low signal circuit is between 20-100 mV. Test the HO2S 1 low signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 18 | Go to Step 17 | ||||||
13 | Test the HO2S 1 high signal circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 18 | Go to Step 15 | ||||||
14 | Test for an intermittent and for a poor connection at the HO2S 1. 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 18 | Go to Step 16 | ||||||
15 | Test for an intermittent and for a poor connection at the engine control module (ECM). 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 18 | Go to Step 17 | ||||||
16 | Replace the HO2S 1. Refer to Heated Oxygen Sensor 1 Replacement . Did you complete the replacement? | -- | Go to Step 18 | -- | ||||||
17 | Replace the ECM. Refer to Engine Control Module Replacement . Did you complete the replacement? | -- | Go to Step 18 | -- | ||||||
18 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 19 | ||||||
19 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK | |||||||
