GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2007 🢒 Colorado Pickup - 2WD 🢒 Brakes 🢒 Park Brake 🢒 DTC P0366

Circuit Description

The exhaust camshaft position (CMP) sensor produces a 4X plus a sync signal for each revolution of the exhaust camshaft. These signals are for control of sequential fuel injection and for exhaust camshaft phaser control. The CMP is connected directly to the powertrain control module (PCM) and consists of the following circuits:

    • 12-volt reference
    • Low reference
    • CMP sensor signal

If the PCM receives an incorrect number of CMP sensor pulses in a given number of CKP sensor pulses, DTC P0366 will set.

The PCM runs 2 tests to diagnose the CMP sensor performance system. It uses a Near Engine Start, CMP fast event based test, and an After Engine Start, CMP slow event based test. The Near Engine Start, CMP fast event based, test runs first upon or during start-up. If the test fails, it will set DTC P0366. If the test passes it will initiate the After Engine Start, CMP slow event based, test and runs this test continuously unless it detects an error and sets DTC P0366.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0366 Exhaust Camshaft Position (CMP) Sensor Performance

Conditions for Running the DTC

Near Engine Start (CMP Fast Event Based) Test

    • The engine is cranking.
    • The medium resolution is less than or equal to 10 counts.
    • DTC P0365 is not set.

After Engine Start (CMP Slow Event Based Test)

    • The engine is running.
    • DTCs P0335, P0336, and P0365 are not set.
    • DTC P0366 runs continuously once the above conditions are met.

Conditions for Setting the DTC

Near Engine Start (CMP Fast Event Based) Test

    • The PCM detects the incorrect number of CMP sensor pulses during two revolutions of the crankshaft.
    • The above condition is met for more than 1 second.

After Engine Start (CMP Slow Event Based Test)

    • The PCM detects the incorrect number of CMP sensor pulses during 2,000 revolutions of the crankshaft.
    • The above condition is met for more than 3 minutes.

Action Taken When the DTC Sets
    • The malfunction indicator lamp (MIL) will illuminate after 2 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. The Freeze Frame and Failure Records buffers will store this information.
    • A history DTC stores.

Conditions for Clearing the MIL/DTC
    • The MIL will turn OFF after 3 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.
    • A scan tool can clear the DTCs.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step verifies that the condition is present.

    2.

  2. This step detects if there is electromagnetic interference (EMI) on the CMP sensor circuits.

Step

Action

Yes

No

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Powertrain Control Module Connector End Views or Engine Controls Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Turn ON the ignition, with the engine OFF.
  2. Clear the DTCs with a scan tool.
  3. Start the engine.
  4. Observe the DTC information with a scan tool.

Did DTC P0341 fail this ignition?

Go to Step 3

Go to Step 4

3

Did any other DTCs fail this ignition cycle?

Go to Diagnostic Trouble Code (DTC) List - Vehicle

Go to Step 5

4
  1. Observe the Freeze Frame/Failure Records for this DTC.
  2. Turn Off the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

Did the DTC fail this ignition?

Go to Step 5

Go to Intermittent Conditions

5

Inspect the camshaft position (CMP) sensor circuits for the following conditions:

    • Routed too close to the ignition coils
    • Routed too close to after-market electrical equipment
    • Routed too close to solenoids, relays, and motors

Did you find and correct the condition?

Go to Step 10

Go to Step 6

6

Test for an intermittent and for a poor connection at the CMP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 10

Go to Step 7

7

Test for an intermittent and for a poor connection at the powertrain control module (PCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 10

Go to Step 8

8
  1. Remove the CMP sensor. Refer to Camshaft Position Sensor Replacement .
  2. Inspect the CMP sensor and the camshaft reluctor wheel for the following conditions:
    3. • Incorrect sensor installation
    • A cracked or broken sensor
    • The sensor coming in contact with the reluctor wheel
    • Excessive air gap between the reluctor wheel and the sensor
    • Foreign material passing between the sensor and the camshaft reluctor wheel
    • Missing teeth in the camshaft reluctor wheel
  3. If you find a condition with the CMP sensor or the camshaft reluctor wheel, refer to Camshaft Position Exhaust Actuator Replacement or Camshaft Position Sensor Replacement .

Did you find and correct the condition?

Go to Step 10

Go to Step 9

9

Replace the CMP sensor. Refer to Camshaft Position Sensor Replacement .

Did you complete the replacement?

Go to Step 10

--

10
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

Did the DTC fail this ignition?

Go to Step 2

Go to Step 11

11

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

Go to Diagnostic Trouble Code (DTC) List - Vehicle

System OK