Component Testing

2006 Chevrolet Cobalt SS, 4D Sedan, StandardSECTION Component Testing
WARNING: This page is about a different car, the 2008 Pontiac G5 and 2008 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.
IMPORTANT: You must perform the Circuit/System Testing in order to verify the integrity of the MAP sensor circuits before proceeding with the Component Testing.

Skewed Sensor Test

  1. Ignition OFF, remove the vacuum source from the MAP sensor.
  2. Ignition ON, observe and record the scan tool MAP sensor pressure parameter. This is the first MAP sensor reading.
  3. With the J 23738-AΒ  or J 35555Β  apply 17 kPa (5 in Hg) of vacuum to the MAP sensor. Observe and record the scan tool MAP sensor pressure parameter. This is the second MAP sensor reading.
  4. Subtract the second MAP sensor reading from the first MAP sensor reading. Verify that the vacuum decrease is within 4 kPa (1 in Hg) of the applied vacuum.
    • If the vacuum decrease is not within the specified range, replace the MAP sensor.
  5. With the J 23738-AΒ  or J 35555Β  , apply 34 kPa (10 in Hg) of vacuum to the MAP sensor. Observe and record the scan tool MAP sensor pressure parameter. This is the third MAP sensor reading.
  6. Substract the third MAP sensor reading from the first MAP sensor reading. Verify that the vacuum decrease is within 4 kPa (1 in Hg) of the applied vacuum.
    • If the vacuum decrease is not within the specified range, replace the MAP sensor.

Erratic Signal Test

  1. Ignition OFF, remove the MAP sensor.
  2. Install a 3A fused jumper wire between the 5-volt reference circuit terminal 1 and the corresponding terminal of the MAP sensor.
  3. Install a jumper wire between the low reference circuit terminal 2 of the MAP sensor and ground.
  4. Install a jumper wire at terminal 3 of the MAP sensor.
  5. Connect a DMM between the jumper wire from terminal 3 of the MAP sensor and ground.
  6. Ignition ON, with the J 23738-AΒ  or J 35555Β  , slowly apply vacuum to the sensor while observing the voltage on the DMM. The voltage should vary between 0-5.2 volts, without any spikes or dropouts.
    • If the voltage reading is erratic, replace the MAP sensor.
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.