DTC P0135 or P0155. Saturn L300/LW300 2003

For 1990-2009 cars only

Makes 🢒 Saturn 🢒 2003 🢒 L300/LW300 🢒 Engine 🢒 Engine Controls - 3.0L (L81) 🢒 DTC P0135 or P0155

Engine Controls Component Views
Engine Controls Schematics

Circuit Description

Heating elements inside the heated oxygen sensor (HO2S) minimize the time required for the sensors to reach operating temperature, and to provide an accurate voltage signal. A low side driver within the engine control module (ECM) is pulse width controlled to provide variable current to the heater elements. During warm-up, the ECM will reduce the ON time to prevent thermal shock to the sensor components from moisture in the exhaust system. The ECM will not allow full HO2S heating until calibrated limits of time, temperature, and intake airflow have been reached. The ECM periodically monitors the HO2S heater operating state by briefly turning OFF the heater low side driver at regular intervals. A small reference voltage is present at the heater low control circuit. When the low side driver is commanded ON, the reference voltage is low. When the low side driver is commanded OFF, the reference voltage is high, close to battery voltage. If the ECM detects that the HO2S has not become active within a certain amount of time, DTC P0135 will set for bank 1 sensor 1, or DTC P0155 will set for bank 2 sensor 1.

Conditions for Running the DTC

•	The engine is running.

•	The Battery Voltage parameter is 10.5-17.3 Volts.

•	The calculated exhaust gas temperature is 550°C (1022°F).

Conditions for Setting the DTC

The HO2S has not become active within 20 seconds of the DTC running.

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.

Step

Action

Values

Yes

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Engine Controls Connector End Views or Engine Control Module Connector End Views

Did you perform the Diagnostic System Check-Engine Controls?

Go to Step 2

Go to Diagnostic System Check - Engine Controls

Important: If any other DTCs are set except for heated oxygen sensor (HO2S) DTCs, refer to the other DTCs first before proceeding with this table.

Start the engine.
Allow the engine to reach operating temperature. Refer to Scan Tool Data List .
Operate the engine at 2,000 RPM for 1 minute.
Observe the affected HO2S lambda value.

Is the HO2S lambda value varying within the specified range?

0.900-1.100

Go to Step 3

Go to Step 4

Observe the Freeze Frame/Failure Records for this DTC.
Turn OFF the ignition for 90 seconds.
Start the engine.
Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

Did the DTC fail this ignition?

Go to Step 4

Go to Intermittent Conditions

Inspect the exhaust system for any leaks upstream from the affected oxygen sensor.
Inspect for any exhaust leaks between sensor 1 and sensor 2.
Repair the exhaust leak as necessary. Refer to Exhaust Leakage in Engine Exhaust.

Did you find and correct the condition?

Go to Step 19

Go to Step 5

Turn OFF the ignition.
Visually/physically inspect the following items:

•	Ensure that the HO2S is securely installed.

•	Disconnect the connector for the HO2S that applies to this DTC.

•	Inspect for terminal corrosion or water intrusion.

•	Inspect the terminal tension at the HO2S connectors.

•	Inspect for damaged wiring.

Repair as necessary. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 19

Go to Step 6

Turn ON the ignition, with the engine OFF.
Measure the voltage from the HO2S input pump current circuit, on the engine harness side, to a good ground with a DMM. Refer to Circuit Testing in Wiring Systems.

Is the voltage within the specified range?

330-360 mV

Go to Step 7

Go to Step 10

Measure the voltage from the HO2S low reference circuit, on the engine harness side, to a good ground with a DMM. Refer to Circuit Testing in Wiring Systems.

Is the voltage within the specified range?

2.4-2.6 mV

Go to Step 8

Go to Step 12

Connect a 3-amp fused jumper wire between the HO2S input pump current circuit, on the engine harness side, and a good ground.
Measure the voltage from the HO2S output pump current circuit, 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?

200 mV

Go to Step 9

Go to Step 13

Turn OFF the ignition.
Remove the jumper wire from the previous step.
Measure the resistance of the following circuits with a DMM:

•	The HO2S heater low control circuit

•	The HO2S heater ignition 1 voltage circuit

•	Refer to Circuit Testing in Wiring Systems.

Is the resistance of either circuit more than the specified value?

5 ohms

Go to Step 16

Go to Step 15

Is the voltage less than the specified value?

340 mV

Go to Step 11

Go to Step 13

Test the HO2S input pump current for the following conditions:

•

an open

•	high resistance

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 19

Go to Step 14

Test the HO2S 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 19

Go to Step 14

Important: The normal voltage on the input pump current circuit is 330-360 mV

Test the HO2S input pump current circuit for a short to any other HO2S circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 19

Go to Step 14

Inspect for shorted terminals and poor connections at the harness connector of 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 19

Go to Step 17

The HO2S may be detecting a lean or rich exhaust condition. Inspect for one of the following conditions:

•	HO2S connector water intrusion

•	An exhaust leak between the HO2S and the engine--Refer to Exhaust Leakage in Engine Exhaust.

•	Vacuum leaks

•	Incorrect fuel pressure-- Refer to Fuel System Diagnosis .

•

Fuel contamination--Water, even in small amounts, can be delivered to the fuel injectors. The water can cause a lean exhaust to be indicated. Excessive alcohol in the fuel can also cause this condition. Refer to Alcohol/Contaminants-in-Fuel Diagnosis for the proper procedure for inspecting for contaminants.

•	Lean fuel injectors--Refer to Fuel System Diagnosis .

•	An inaccurate mass air flow (MAF) sensor

•	HO2S element contamination.

Repair any of the above or similar engine conditions as necessary.

Did you find and correct the condition?

Go to Step 19

Go to Step 18

Repair the circuit with high resistance. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 19

Replace the ECM. Refer to Engine Control Module Replacement .

Did you complete the replacement?

Go to Step 19

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 19

Clear the DTCs with a scan tool.
Turn OFF the ignition for 90 seconds.
Start the engine.
Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

Did the DTC fail this ignition?

Go to Step 2

Go to Step 20

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

Go to Diagnostic Trouble Code (DTC) List

System OK