P1130
P1130 O2 Bank 1 Sensor 1 Low Signal Variance
Circuit Description
The powertrain control module (PCM)/engine control module (ECM) constantly monitors the oxygen sensor (O2S 1) activity after cold start. During the monitoring period, the PCM/ECM determines if the oxygen sensor (O2S 1) is functioning properly by monitoring time for O2S 1 to become active. The PCM/ECM counts the elapsed time to obtain the change in O2S 1 voltage, +126 mV or -126 mV, from mean O2S 1 bias voltage. If the change in O2S 1 is too low within the calibrated time, DTC P1130 will set.
If the O2S 1 pigtail wiring, connector or terminal are damaged, the entire O2S 1 assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have a clean air reference provided to it. This clean air reference is obtained by way of the O2S 1 wire(s). Any attempt to repair the wires, connector or terminals could result in the obstruction of the air reference and degrade O2S 1 performance.
Conditions for Setting the DTC
- DTCs P0131, P0132 and P0134 are not set.
- Start up Engine Coolant Temperature (ECT) is less than 32 °C (90 °F).
- Start up Intake Air Temperature (IAT) is less than 32 °C (900 °F).
- Difference between start up ECT and IAT is less than 7 °C (45 °F).
- Voltage before start is between 11 volts and 18 volts.
- O2S 1 output at key ON is between 400 mV and 500 mV.
- Throttle Position Sensor (TPS) is less than 50%.
- Average air flow is greater than 4 g/sec.
Action Taken When the DTC Sets
- The PCM/ECM will illuminate the malfunction indicator lamp (MIL).
- Open loop fuel control will be in effect.
- The PCM/ECM will store conditions which were present when the DTC was set as Freeze Frame and in the Failure Records data.
- A history DTC is stored.
Conditions for Clearing the MIL/DTC
- The PCM/ECM will turn the MIL off on the third consecutive trip cycle during which the diagnostic has been run and the fault condition is no longer present.
- A history DTC will clear after 40 consecutive warm-up cycles have occurred without a fault.
- DTC can be cleared by using the scan tool.
Diagnostic Aids
An intermittent may be caused by rubbed through wire insulation or a wire contacting the exhaust. Check for poor connection or damaged harness inspect harness connectors for the following conditions:
- Improper mating
- Broken locks
- Improperly formed
- Damaged terminals
- Poor terminal-to-wire connection
- Damaged harness
Step 1 - 6:
Step 7 - 12:
Test Description
The number(s) below refer to step(s) on the diagnosis table.
1. On-Board Diagnostic (OBD II) 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. Make sure DTCs P0131, P0132 and P0134 are not set.
3. If the O2S 1 pigtail wiring, connector or terminals are damaged, the entire O2S 1 assembly must be replaced. Do not attempt to repair the wires, connector or terminals. For the sensor to function properly, a clean air reference must be provided to it. This clean air reference is obtained through the O2S 1 wire(s). Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degrade O2S 1 performance. An intermittent may be caused by a poor connection, rubbed-through wire insulation or a wire broken inside the insulation.
9. Perform an intermittent test. If the connections and the harness check OK, monitor a Digital Voltmeter (DVM) connected between the ECT sensor signal circuit and ground circuit terminals while moving the related connectors and the wiring harness. If a fault is induced, the resistance reading will change. This may help to isolate the location of the malfunction.
10. The replacement PCM/ECM must be reprogrammed. Refer to the latest Techline procedure for reprogramming the PCM/ECM.