Circuit Description
The crankshaft position (CKP) sensor contains 2 hall-effect switches in one housing. This sensor configuration produces 2 separate CKP sensor pulses. These pulses occur when 2 interrupter rings, mounted to the crankshaft balancer, the outer one containing 18 evenly spaced windows and blades, the inner one containing 3 unevenly spaced windows and blades, pass by the sensors. The 18X sensor produces 18 pulses per engine revolution. The 3X sync sensor produces 3 pulses per engine revolution, each pulse representing a pair of companion cylinders. Both sensors are connected directly to the ignition control module (ICM). The sensor wiring includes the following circuits:
| • | The CKP sensor 1 signal circuit |
| • | The CKP sensor 2 signal circuit |
| • | A shared 12-volt reference circuit |
| • | A shared low reference circuit |
The ICM uses the sensors to determine the engine position and speed. A signal converter within the ICM, using the CKP sensor 1 18X pulse, produces a digital 3X output signal to the powertrain control module (PCM) on the low resolution engine speed signal circuit. The PCM monitors the low resolution engine speed signal circuit for errors. If the PCM receives an incorrect number of signals from the ICM, DTC P0386 sets.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0386 Crankshaft Position (CKP) Sensor B Performance
Conditions for Running the DTC
| • | The engine run time is more than 3 seconds. |
| • | DTC P0386 runs continuously when the above condition is met. |
Conditions for Setting the DTC
| • | The PCM detects The following for every 2 engine revolutions: |
| - | 36 medium resolution engine speed signals |
| - | 1 CMP sensor signal |
| - | A number other than 0 or 6 low resolution engine speed signals |
| • | The condition exists for more than 8 seconds. |
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Clear the MIL and the DTC with a scan tool. |
Diagnostic Aids
- Attempt to start the engine. The engine should start and run.
- Monitor the CKP Sensor A and the CKP Sensor B parameters. The parameters should increment from 0-255 continuously with the engine running or cranking.
- Using the Live Plot function on the scan tool, select the CKP Sensor A and the CKP Sensor B parameters. Change the minimum spec to 400 RPM and the maximum spec to 3,500 RPM.
- Observe the scan tool.
- Crank the engine. If the engine starts quickly accelerate and release the accelerator pedal several times. Do not exceed 3,200 RPM. The graphed lines on the Live Plot display should track together across the screen.
Step | Action | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module Connector End Views | |||||||||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |||||||
2 |
Did the DTC fail this ignition? | Go to Step 3 | Go to Testing for Intermittent Conditions and Poor Connections | ||||||
3 |
Did you find and correct the condition? | Go to Step 9 | Go to Step 4 | ||||||
4 |
Did the Duty Cycle increment? | Go to Step 7 | Go to Step 5 | ||||||
5 | Test for an intermittent and for a poor connection at the ignition control module (ICM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 9 | Go to Step 6 | ||||||
6 | 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 9 | Go to Step 8 | ||||||
7 | Replace the CKP sensor. Refer to Crankshaft Position Sensor Replacement . Did you complete the replacement? | Go to Step 9 | -- | ||||||
8 | Replace the ICM. Refer to Ignition Control Module Replacement . Did you complete the replacement? | Go to Step 9 | -- | ||||||
9 |
Did the DTC fail this ignition? | Go to Step 2 | Go to Step 10 | ||||||
10 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | System OK | |||||||
