Circuit Description
The PCM continuously monitors the oxygen sensor 1 (O2S 1) activity for 100 seconds. During the monitor period, the PCM counts the number of times that the O2S 1 switches from rich to lean and from lean to rich. You can determine a total for all of the switches with this information. If the number of switches is too low, a DTC P1133 will set.
Conditions for Setting the DTC
| • | DTC s P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0171, P0200, P0300, P0301, P0302, P0303, P0304, P0341, P0404, P0506, P0507, P0601, P0602 not set. |
| • | Engine speed is between 1600 RPM and 2600 RPM. |
| • | TP angle is between 9% and 20%. |
| • | Evaporative emissions control system is commanded open for greater than 36% PWM. |
| • | Purge learned memory is greater than 191. |
| • | The above conditions are present for at least 100 seconds. |
| • | The number of rich to lean counts is less than 10 or the lean to rich counts is less than 15. |
Action Taken When the DTC Sets
| • | The malfunction indicator lamp (MIL) will illuminate after two consecutive ignition cycles in which the diagnostic runs with the malfunction present. |
| • | The PCM will record the operating conditions at the time that the diagnostic fails. This information will store in the Freeze Frame and Failure Records buffers. |
| • | A history DTC stores. |
| • | The coolant fan turns ON. |
Conditions for Clearing the MIL/DTC
| • | The MIL will turn OFF after three 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. |
| • | The MIL/DTCs can be cleared by using the scan tool. |
Diagnostic Aids
DTC P1133 is most likely caused by one of the following:
| • | Fuel pressure--The system will go rich if fuel pressure is to high. The PCM can compensate for some increase, however, if it gets too high, a DTC P0172 will be set. Refer to Fuel System Diagnosis . |
| • | Leaking injector--A leaking or malfunctioning injector can cause the system to go rich. |
| • | MAP sensor--An output that causes the PCM to sense a higher than normal manifold pressure (low vacuum) can cause the system to go rich. Disconnecting the MAP sensor will allow the PCM to set a fixed value for the MAP sensor. Substitute a different MAP sensor if the rich condition is gone while the sensor is disconnected. |
| • | Pressure regulator--Check for a leaking fuel pressure regulator diaphragm by checking for the presence of liquid fuel in the vacuum line to the regulator. |
| • | TP sensor--An intermittent TP sensor output will cause the system to go rich due to a false indication of the engine accelerating. |
| • | O2S 1 contamination--Inspect O2S 1 for silicone contamination from fuel or use of improper RTV sealant. The sensor may have a white powdery coating and result in a high but false voltage signal (rich exhaust indication). The PCM will then reduce the amount of fuel delivered to the engine causing a severe surge or driveability problem. |
Test Description
The numbers below refer to the step numbers on the Diagnostic Table.
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The Powertrain OBD System Check prompts you to complete some of the basic checks and to store the freeze frame and failure records data on the scan tool if applicable. This creates an electronic copy of the data captured when this DTC set. The scan tool stores this data for later reference.
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Reprogram the replacement PCM and perform the crankshaft position system variation learn procedure. Refer to the latest Techline procedures for PCM reprogramming and the Crankshaft Position System Variation Learn .
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If no malfunctions are present at this point and no additional DTCs were set, refer to Diagnostic Aids for additional checks and information.
Step | Action | Value(s) | Yes | No | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | |||||||||||||||||
2 |
Are any component DTCs set? | -- | Go to Component DTC table | |||||||||||||||
3 |
Do the parameters show fewer transitions than the specified values? | 1-1 | ||||||||||||||||
4 |
Was a problem present in any of the above areas? | -- | ||||||||||||||||
5 |
Caution: Avoid contact with moving parts and hot surfaces while working around a running engine in order to prevent physical injury. Was a repair necessary? | -- | ||||||||||||||||
6 |
Does the scan tool voltage indicate the O2S 1 voltage within the specified value? | 407-509 mV | ||||||||||||||||
7 | Connect a jumper wire between the O2S 1 high circuit (PCM side) signal circuit to ground. Does the scan tool voltage indicate that the O2S 1 voltage is below the specified value? | 200 mV | ||||||||||||||||
8 |
Caution: Avoid contact with moving parts and hot surfaces while working around a running engine in order to prevent physical injury. Notice: Determine and correct the cause of the contamination in order to prevent damage to the replacement sensors.
Is the action complete? | -- | -- | |||||||||||||||
9 | Repair the condition as necessary. Is the action complete? | -- | -- | |||||||||||||||
10 |
Is the action complete? | -- | -- | |||||||||||||||
11 |
Does the O2S 1 voltage measure above the specified value? | 407 mV | ||||||||||||||||
12 |
Was an O2S 1 low circuit problem found and corrected? | 5ohms | ||||||||||||||||
13 |
Was an O2S 1 signal circuit problem found and corrected? | 5ohms | ||||||||||||||||
14 |
Did the terminal require replacement? | -- | ||||||||||||||||
15 |
Did the terminal require replacement? | -- | ||||||||||||||||
Replace the PCM. Refer to the Powertrain Control Module Replacement/Programming . Is the action complete? | -- | -- | ||||||||||||||||
17 |
Does the scan tool indicate that this diagnostic has ran and passed? | -- | ||||||||||||||||
Check to see if any additional DTCs are set. Does the scan tool display any DTCs that you have not diagnosed? | -- | Go to the applicable DTC table | System OK Refer to Diagnostic Aids |
