P0134

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

The Powertrain Control Module (PCM) supplies a reference voltage of about 0.45 volt to the Oxygen Sensor (O2S). The O2S 1 voltage varies within a range of about 1.0 volt when the exhaust is rich, down to about 0.10 volt when the exhaust is lean.

CONDITIONS FOR SETTING THE DTC

^ DTCs P0106, P0107, P0108, P0112, P0116, P0117, P0118, P0121, P0122, P0123, P0171, P0200, P0300, P0301, P0302, P0303, P0304, P0341, P0404, P0506, P0507, P0601, P0602 not set.

^ Air flow is greater than 3 grams per second.

^ Engine Coolant Temperature (ECT) is greater than 70°C (158°F).

^ Throttle Position (TP) angle is between 4% and 56% for 20 seconds.

^ Engine run time is greater than 30 seconds.

^ 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.

^ The PCM will record the operating conditions at the time that the diagnostic fails. The Freeze Frame and Failure Records buffers will store this information.

^ A history DTC stores.

CONDITIONS FOR CLEARING THE MIL/DTC

^ The MIL will turn off after 3 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.

^ A scan tool can clear the DTCs.

DIAGNOSTIC AIDS

^ When the oxygen sensor pigtail wiring, connector or terminal are damaged, the entire oxygen sensor assembly must be replaced. Do not attempt to repair the wiring, the connector or the terminals. In order for the sensor to function properly, the O2S must have a clean air reference. This clean air reference is obtained by way of the oxygen sensor wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degrade the oxygen performance of the sensor.

^ The normal scan tool voltage varies between 150 mV to 850 mV (0.15 volt to 0.85 volt) when in a Closed Loop. The DTC P0134 sets in approximately 88 seconds when the voltage remains between 0.407 volt and 0.509 volt. The system will go into an Open Loop in about 30 seconds.

TEST DESCRIPTION

Number(s) below refer to the step number(s) on the Diagnostic Table.

1. The Powertrain OBD System Check prompts the technician to complete some basic checks and 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 information is then stored on the scan tool for later reference.

2. During engine warm-up, the O2S 1 should warm-up and its voltage output should vary between 150 mV and 850 mV. When O2S 1 voltage varies, the engine will go into Closed Loop. This step determines if the O2S 1 is operating properly.

4. This will determine if the sensor is malfunctioning or the wiring or PCM is the cause of the DTC P0134.

6. Use only a high impedance digital volt ohmmeter for this test. This test checks the continuity of CKT 412 and CKT 413; if CKT 413 is open, the PCM voltage on CKT 412 will be over 0.6 volt (600 mV).

8. Replacement PCMs must be reprogrammed and the crankshaft position system variation procedure must be performed. Refer to the latest Techline information for PCM reprogramming and also refer to the Crankshaft Position (CKP) System Variation Learn Procedure for the Crankshaft Position System Variation Procedure.