GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1998 🢒 GMC Suburban - 2WD 🢒 DTC 🢒 DTC P0237 Turbocharger Boost Sensor Circuit Low Voltage

Object Number: 185023 Size: LF
Engine Controls Components
Engine Sensors
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The PCM operates a solenoid to control boost. This solenoid is normally open. By providing a ground path the PCM energizes the solenoid which then allows vacuum to pass to the wastegate valve. During normal operation, the PCM compares its wastegate duty cycle signal with the boost signal and makes corrections in the duty cycle accordingly.

Conditions for Running the DTC
    • The PCM performs this DTC diagnostic continuously.
    • The ignition switch is in the ON position.

Conditions for Setting the DTC
    • The boost pressure is less than 40 kPa.
    • All diagnostic conditions met for 10 seconds.

Action Taken When the DTC Sets
    • The PCM illuminates the malfunction indicator lamp (MIL) on the second consecutive drive trip that the diagnostic runs and fails.
    • The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the Failure Records will store this information. If the diagnostic reports a failure on the second consecutive drive trip, the Freeze Frame records the operating conditions at the time of failure and updates the Failure Records.

Conditions for Clearing the MIL/DTC
    • The PCM will turn the MIL off after three consecutive trips without a fault condition.
    • A History DTC clears after forty consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures
    • The use of a scan tool.

Diagnostic Aids

Very little boost can be attained by revving the engine in neutral. If the boost sensor signal circuit is open or shorted to ground, the boost solenoid will show a zero duty cycle.

An intermittent may be caused by the following:

    • Poor connections.
    • Rubbed through wire insulation.
    • Broken wire inside the insulation.

Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table.

  1. This step will determine if DTC P0237 is the result of a hard failure or an intermittent condition.

    2.

  2. This step simulates conditions for a DTC P0237. If the PCM recognizes the change, the PCM and signal circuit are OK.

    3.

  3. In this step, components that share the 5 volt reference can cause the reference voltage to be shorted to ground. This can be checked by disconnecting each component that shares the 5 volt reference one at a time, including the PCM while checking for continuity on that circuit to chassis ground.

Step

Action

Value(s)

Yes

No

1

Important: Before clearing the DTCs, use the scan tool Capture Info to save the Freeze Frame and failure records for reference. The control module's data is deleted once the Clear Info function is used.

Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2
  1. Connect a Scan tool.
  2. Start the engine and let the engine idle.
  3. Observe the Boost pressure display on the Scan tool

Does the scan tool display a Boost Pressure less than or equal to the specified value?

40 kPa

Go to Step 3

Go to Step 5

3

  1. Turn the ignition OFF.
  2. Disconnect the Boost sensor electrical connector.
  3. Jumper the Boost sensor 5 volt reference to the Boost sensor signal circuit at the harness.
  4. Turn the ignition ON.

Does the scan tool display a Boost Pressure greater than or equal to the specified value?

202 kPa

Go to Step 6

Go to Step 4

4
  1. Turn the ignition OFF.
  2. The Boost sensor still disconnected.
  3. Remove the jumper wire.
  4. Probe the Boost sensor signal circuit at the harness with a test light connected to B+.
  5. Turn the ignition ON.

Does the scan tool display a Boost Pressure greater than or equal to the specified value?

202 kPa

Go to Step 8

Go to Step 7

5

The DTC is intermittent. If no additional DTCs are stored, refer to Diagnostic Aids. If additional DTCs are stored, refer to those table(s) first.

Are any additional DTCs stored?

--

Go to the Applicable DTC Table

Go to Diagnostic Aids

6
  1. Check for a proper connection at the Boost sensor.
  2. If a problem is found, repair as necessary.

Was a problem found?

--

Go to Step 13

Go to Step 10

7
  1. Check for the following in Boost sensor signal circuit.
    2. • For an open.
    • For a short to ground.
  2. If a problem is found, repair as necessary.

Was a problem found?

--

Go to Step 13

Go to Step 11

8
  1. Check for an open in the Boost sensor 5 volt reference circuit.
  2. If a problem is found, repair as necessary.

Was a problem found?

--

Go to Step 13

Go to Step 9

9

  1. Check for a short to ground in the Boost sensor 5 volt reference circuit.
  2. If a problem is found, repair as necessary.

Was a problem found?

--

Go to Step 13

Go to Step 12

10

Replace the Boost sensor. Refer to Boost Sensor Replacement .

Is the action complete?

--

Go to Step 13

--

11
  1. Check the terminal connectors at the PCM for a proper connections.
  2. If a problem is found, repair as necessary.

Was a problem found?

--

Go to Step 13

Go to Step 12

12

Replace the PCM.

Important: The new PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming .

Is the action complete?

--

Go to Step 13

--

13
  1. Using the scan tool, clear the DTCs.
  2. Start the engine.
  3. Allow the engine to idle at normal operating temperature.
  4. Select DTC and the Specific DTC function.
  5. Enter the DTC number which was set.
  6. Operate the vehicle, with the Condition for Setting this DTC, until the scan tool indicates the diagnostic Ran.

Does the scan tool indicate the diagnostic Passed?

--

Go to Step 14

Go to Step 2

14

Does the scan tool display any additional undiagnosed DTCs?

--

Go to the Applicable DTC Table

System OK