DTC P0135 or P0155. Chevrolet Chevy C Silverado

For 1990-2009 cars only

Makes 🢒 Chevrolet 🢒 2001 🢒 Chevy C Silverado - 2WD 🢒 Engine 🢒 Engine Controls - 4.8L, 5.3L, and 6.0L 🢒 DTC P0135 or P0155

DTC P0135 or P0155 w/LQ4 w/Denso HO2S

Circuit Description

This diagnostic applies only to vehicles built with Denso heated oxygen sensors. To identify the heated oxygen sensor refer to

Oxygen Sensor Identification (4.8L/5.3L/6.0L)


(1)	Delphi Sensor - Case Grounded
(2)	Denso Sensor - Isolated Grounded

in Engine Controls Component Views.

The powertrain control module (PCM) supplies a bias voltage of approximately 450 mV on the heated oxygen sensor (HO2S) signal high and low circuits. With the engine running voltage is supplied to the HO2S heater. As the heater reaches the operating temperature, the HO2S voltage responds by changing from a bias voltage range to the normal operation.

The PCM runs the heater test only on a cold start (depends on the cumulative air flow) and only once an ignition cycle. When you start the engine the PCM monitors the HO2S voltage. When the HO2S voltage goes above or below the bias range threshold, the PCM determines how much time it took. If the PCM detects that the process took too much time for the HO2S to enter into normal operating range, a DTC sets. The time the process takes the HO2S to reach operating temperature is based on the amount of air that flows into the engine.

Conditions for Running the DTC

•

DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0131, P0132, P0134, P0137, P0138, P0140, P0151, P0152, P0154, P0157, P0158, P0160, P0200, P0300, P0401, P0404, P0405, P0410, P0440, P0442, P0446, P0452, P0453, P1120, P1125, P1220, P1221, P1258, P1404, P1415, P1416, P1514, P1515, P1516, P1517 or P1518 are not set.

•	The HO2S voltage is between 425-465 mV at engine start-up.

•	The intake air temperature (IAT) and the engine coolant temperature (ECT) are less than 50°C (122°F) and are within 8°C (14.5°F) of each other at engine start-up.

•	The ignition 1 signal is between 9-18 volts.

•	Intrusive tests are not in progress.

•	The scan tool output controls are not active.

•	The scan tool is disconnected.

Conditions for Setting the DTC

The HO2S voltage remains within 150 mV of the start-up voltage for a predetermined amount of time, based on ECT and air flow.

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

Important: Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM connector gaskets when diagnosing or replacing the PCM. Ensure that the gaskets are installed correctly. The gaskets prevent water intrusion into the PCM.

Using the Freeze Frame/Failure Records data may aid in locating an intermittent condition. If you cannot duplicate the DTC, the information included in the Freeze Frame/Failure Records can help determine how many miles since the DTC set. The Fail Counter and Pass Counter can also help determine how many ignition cycles the diagnostic reported a pass or a fail. Operate the vehicle within the same Freeze Frame conditions such as RPM, load, vehicle speed, and temperature that you observed. This will isolate when the DTC failed. For an intermittent condition, refer to Intermittent Conditions .

An oxygen supply inside the HO2S is necessary for proper operation. The HO2S wires provide the supply of oxygen. Inspect the HO2S wires and connections for breaks or contamination. Refer to Heated Oxygen Sensor Wiring Repairs in Wiring Systems.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

After the HO2S heater is commanded ON, the HO2S heater heats up causing the HO2S signal voltage to either increase or decrease. This indicates that the HO2S heater is OK.

Both HO2S sensors must be disconnected to isolate a short to ground in the HO2S heater high control circuit.

Resistance within the specified range indicates the HO2S heater is OK.

Step

Action

Values

Yes

Schematic Reference: Engine Controls Schematics

Important: This diagnostic applies only to vehicles built with Denso heated oxygen sensors. To identify the heated oxygen sensor, refer to

Oxygen Sensor Identification (4.8L/5.3L/6.0L)


(1)	Delphi Sensor - Case Grounded
(2)	Denso Sensor - Isolated Grounded

in Engine Components Views.

Did you perform the Diagnostic System Check-Engine Controls?

Go to Step 2

Go to Diagnostic System Check - Engine Controls

Important: If DTC P0300 is set, diagnose that DTC first. Refer to Diagnostic Trouble Code (DTC) List .

Important: Allow the engine to cool for one-half hour before proceeding with this diagnostic. This allows the HO2S signal voltage to return to bias voltage, approximately 447 mV.

Install a scan tool.
Turn ON the ignition, with the engine OFF.
Command the HO2S heater ON with a scan tool.
Immediately observe the affected HO2S voltage for 2 minutes.

Does the HO2S voltage go from bias voltage to more than or less than the specified range?

350-550 mV

Go to Step 3

Go to Step 4

Observe the Freeze Frame/Failure Records data for this DTC.
Turn OFF the ignition for 30 seconds.
Start the engine.
Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text, or as close to the Freeze Frame/Failure Records data that you observed.

Does the DTC fail this ignition?

Go to Step 4

Go to Intermittent Conditions

Are Both DTC P0135 and DTC P0155 set?

Go to Step 6

Go to Step 5

Turn OFF the ignition.
Disconnect the affected HO2S connector.
Probe the HO2S heater high control circuit with a test lamp connected to a good ground.
Turn ON the ignition, with the engine OFF
Command the HO2S heater ON with a scan tool.

Does the test lamp illuminate?

Go to Step 7

Go to Step 8

Disconnect HO2S bank 1 sensor 1 connector.
Disconnect HO2S bank 2 sensor 1 connector.
Probe the HO2S bank 1 sensor 1 heater high control circuit with a test lamp connected to a good ground.
Turn ON the ignition, with the engine OFF.
Command the HO2S heater ON with a scan tool.

Does the test lamp illuminate?

Go to Step 7

Go to Step 8

Connect a test lamp between the affected HO2S heater high control circuit and the HO2S heater low reference circuit.
Command the HO2S heater ON with a scan tool.

Does the test lamp illuminate?

Go to Step 9

Go to Step 11

Disconnect the PCM connector containing the HO2S heater high control circuit. Refer to Powertrain Control Module Replacement .
Test the HO2S heater high control circuit for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 16

Go to Step 12

Important: Perform the following test on HO2S bank 1 sensor 1 and HO2S bank 2 sensor 1. A condition in either sensor will cause this DTC to set.

Test the HO2S heater high control circuit, sensor side, for a short to the HO2S body. Refer to Circuit Testing in Wiring Systems.

Did you find the condition?

Go to Step 15

Go to Step 10

Important: Perform the following test on HO2S bank 1 sensor 1 and HO2S bank 2 sensor 1. A condition in either sensor will cause this DTC to set.

Measure the resistance between the HO2S heater high control circuit, sensor side, and the HO2S heater low reference circuit, sensor side. Refer to Circuit Testing in Wiring Systems.

Does the resistance of either sensor measure above or below the specified range?

2-50 ohms

Go to Step 15

Go to Step 13

Disconnect the PCM connector containing the HO2S heater low reference circuit. Refer to Powertrain Control Module Replacement .
Test the HO2S heater low reference circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 16

Go to Step 12

Inspect for poor connections at the harness connector of 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 16

Go to Step 14

Inspect for poor connections at the harness connector of the affected HO2S. 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 16

Go to Step 15

Replace the PCM. Refer to Powertrain Control Module Replacement .

Did you complete the replacement?

Go to Step 16

Replace the affected HO2S refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 or Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 .

Did you complete the replacement?

Go to Step 16

Use the scan tool in order to clear the DTCs.
Disconnect the scan tool.
Turn OFF the ignition for 30 seconds.
Start the engine.
Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.
Install the scan tool.

Does the DTC run and pass?

Go to Step 17

Go to Step 2

With a scan tool, observe the stored information, Capture Info.

Does the scan tool display any DTCs that you have not diagnosed?

Go to Diagnostic Trouble Code (DTC) List

System OK