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Home >> GMC >> 2003 >> Safari Van Cargo, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 85 (Engine Controls - Self-Diagnostics - 8.1L) >> Diagnostic Tests >> DTC P1134 & P1154: Ho2S Transition Time Ratio - Bank 1 & 2, Sensor 1 >> Test Description

Test Description

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The numbers below refer to the step numbers in the diagnostic procedures.

  1. 2

    When DTCs P1134 and P1154 are set at the same time, this is a good indication that a fuel contamination condition is present.

  2. 4

    The use of leaded fuel may be indicated by the removal or tampering of the fuel filler restrictor.

  3. 7

    Even small exhaust leaks can cause a slow response from the HO2S.

  4. 12

    An HO2S contaminated by silicone will have a white, powdery deposit on the portion of the HO2S that is exposed to the exhaust stream. The usual cause of the contamination is the use of unapproved silicone RTV engine gasket material or the use of silicone-based sprays or fluids within the engine. If the cause of this contamination is not corrected, the replacement HO2S will also be contaminated.

  5. 13

    If the voltage observed in step  8 is less than the range specified, a short between the high and low circuits or a short between the high circuit and ground is indicated. With the HO2S and the PCM disconnected the resistance between the high and low circuits and the resistance between the high circuit and ground should measure infinite. If the voltage observed in Step 8 is more than the range specified a short between the high circuit and a voltage source is indicated.

  6. 14

    If the voltage observed in step  9 is not below the voltage specified, a high resistance in the high or low circuit is indicated. Good circuit continuity measures less than 5 ohms with the PCM and sensor disconnected. Measure between the PCM connector and the HO2S connector. Ensure that the PCM terminal contact is good.

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