DTC P1134 HO2S Transition
The PCM monitors the
Heated Oxygen Sensor (HO2S) activity. During the monitor period the PCM counts
the number of times that the HO2S responds from rich to lean and from lean to
rich and adds the amount of time it took to complete all transitions. With this
information, an average time for all transitions can be determined. The PCM
then divides the rich to lean average by the lean to rich average to obtain a
ratio. A DTC P1134 sets if the HO2S ratio is not within range.
Conditions
for Setting the DTC
- DTCs P0102, P0103, P0112, P0113,
P0117, P0118, P0125, P0335, P0336, P0351-P0358, P1120, P1220, P1221, P1258 not set.
- The fuel system is operating in
Closed Loop.
- The engine run time is greater than
2.0 seconds.
- The engine speed is greater than
1000 RPM but less than 2300 RPM.
- The ignition voltage is greater than
9.0 volts.
- The engine coolant temperature is
greater than 65°C (149°F).
- The MAF is between 15 g/s and 35
g/s.
- The EVAP purge duty cycle is greater
than 0%.
Conditions
for Setting the DTC
The PCM determines that
the HO2S transition time ratio is not at the expected value.
Action
Taken When the DTC Sets
- The PCM illuminates the malfunction
indicator lamp (MIL) on the second consecutive ignition cycle that the
diagnostic runs and fails.
- The PCM records the operating
conditions at the time the diagnostic fails. The first time the diagnostic
fails, the PCM stores this information in the Failure Records. If the
diagnostic reports a failure on the second consecutive ignition cycle, the
PCM records the operating conditions at the time of the failure. The PCM
writes the conditions to the Freeze Frame and updates the Failure Records.
Conditions
for Clearing the MIL/DTC
- The PCM turns OFF the malfunction
indicator lamp (MIL) after 3 consecutive ignition cycles that the
diagnostic runs and does not fail.
- A last test failed, or current DTC,
clears when the diagnostic runs and does not fail.
- A history DTC clears after
40 consecutive warm-up cycles, if no failures are reported by this or
any other emission related diagnostic.
- Use a scan tool in order to clear
the MIL and the DTC.
- Using the Freeze Frame and/or
Failure Records data may aid in locating an intermittent condition. If the
DTC cannot be duplicated, the information included in the Freeze Frame
and/or Failure Records data can be useful in determining how many miles
since the DTC set. The Fail Counter and Pass Counter can also be used to
determine how many ignition cycles the diagnostic reported a pass and/or a
fail. Operate vehicle within the same freeze frame conditions (RPM, load,
vehicle speed, temperature etc.) that you observed. This will isolate when
the DTC failed.
- An oxygen supply inside the HO2S is
necessary for proper operation. This supply of oxygen is provided through
the HO2S wires. All HO2S wires and connections should be inspected for
breaks or contamination. Refer to Heated
Oxygen Sensor (HO2S) Wiring Repairs In Wiring Systems.
For an intermittent,
refer to Symptoms
.
The numbers below refer
to the step numbers on the diagnostic table.
- Certain RTV silicone
gasket materials give off vapors that can contaminate the HO2S. There is
also a possibility of silicone contamination caused by silicone in the
fuel. If the sensors appear contaminated by silicone and all the silicone
se
|
Step |
Action |
Value(s) |
Yes |
No |
|
Did
you perform the Powertrain On-Board Diagnostic
(OBD) System Check? |
-- |
|||
|
Important If any DTCs are set (Except
P1153), refer to those DTCs before proceeding with this diagnostic table.
Does
the scan tool indicate DTC P1133 test failed? |
-- |
Go to Diagnostic Aids |
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|
Did
the scan tool also indicate P1153 test failed? |
-- |
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Did
you isolate an exhaust leak? |
-- |
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|
Visually/physically
inspect the following items:
Did
you find a condition in any of the above areas? |
-- |
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Is
the HO2S voltage within the specified range? |
350-550 mV |
|||
Is
the HO2S voltage below the specified value? |
200 mV |
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|
Important Before replacing a sensor,
determine and correct the cause of the contamination. Inspect for the following
conditions:
Replace
the affected Heated Oxygen sensor. Refer to Heated
Oxygen Sensor (HO2S) Replacement - Bank 1 or Heated
Oxygen Sensor (HO2S) Replacement - Bank 2 . Is the action complete? |
-- |
-- |
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|
Repair
the condition as necessary. Is the action complete? |
-- |
-- |
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|
Repair
the open Bank 1 HO2S 1 low signal circuit or grounded Bank 1 HO2S 1 high
signal circuit. Refer to Intermittents and Poor Connections Diagnosis in
Wiring Systems. Is the action complete? |
-- |
-- |
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|
Repair
the open Bank 1 HO2S 1 high signal circuit or faulty PCM connections. Refer
to Intermittents and Poor Connections Diagnosis in
Wiring Systems. Is the action complete? |
-- |
-- |
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|
Replace
the Bank 1 HO2S 1. Refer to Heated
Oxygen Sensor (HO2S) Replacement - Bank 1 . Is the action complete? |
-- |
-- |
||
Does
the scan tool indicate that this test ran and passed? |
-- |
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|
Select
the Capture Info option and the Review Info option using the scan tool. Does
the scan tool display any DTCs that you have not diagnosed? |
-- |
Go to the applicable
DTC table |
System OK |