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Home >> GMC >> 2006 >> Sierra 1500 HD, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1385 (Engine Controls And Fuel - 6.6L - DTC P1448 To DTC P2510) >> DTC P2122, P2123, P2127, P2128, or P2138 >> Component Testing

Component Testing

WARNING: This page is about a different car, the 2009 GMC Sierra, 2009 GMC Cab & Chassis Sierra, 2009 Chevrolet Silverado, and 2009 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: You must perform the Circuit/System Testing to verify the integrity of the APP circuits before proceeding with the Component Testing.
  1. Ignition OFF, install a 3 A fused jumper wire between the 5 V reference circuit terminal of the affected APP sensor and 5 V.
  2. Install a jumper wire between the low reference circuit terminal and a ground.
  3. Install a jumper wire at the signal circuit terminal of the affected sensor.
  4. Ignition ON, sweep the sensor through the entire range while monitoring the voltage between the signal terminal jumper wire and the low reference terminal with a DMM. The voltage should vary between 0.80-4.75 V for APP sensor 1 and 0.30-2.50 V for APP sensor 2 without any spikes or dropouts.
    • If the voltage is not within the specified range or is erratic, replace the APP sensor assembly.
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