DTC P0237 Turbocharger Boost Sensor Circuit Low Voltage. GMC Truck Savana 1998

For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 1998 🢒 Savana 🢒 Engine 🢒 Engine Controls - 6.5L 🢒 DTC P0237 Turbocharger Boost Sensor Circuit Low Voltage

Engine Controls Components
Cell 22: Sensor Controls
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The powertrain control module (PCM) controls boost using the turbocharger wastegate solenoid. The solenoid is pulse width modulated (PWM). When the wastegate solenoid is not energized, the vacuum to the turbocharger wastegate solenoid is vented to atmosphere through the solenoid. As the pulse width is increased by the PCM, more vacuum is applied through the solenoid to the wastegate actuator. At idle a higher vacuum to the wastegate actuator helps keep the wastegate closed. At higher engine speeds the vacuum supplied by the solenoid is less, allowing the turbocharger boost pressure to overcome the wastegate actuator.

Conditions for Setting the DTC

•	The Boost Pressure is less than 40 kPa.

•	The condition was met for 2 seconds.

Action Taken When the DTC Sets

•	The PCM illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive drive trip 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 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 will clear after forty consecutive warm-up cycles during which the diagnostic does not fail (the coolant temperature has risen 22°C (40°F) from the start up coolant temperature and the engine coolant temperature exceeds 71°C (160°F) during that same ignition cycle).

•	Use of a Scan Tool will clear the DTC codes.

Diagnostic Aids

An intermittent may be caused by the following:

•	Poor connections.

•	Rubbed through wire insulation.

•	Broken wire inside the insulation.

Check for opens or shorts to ground in the signal wire.

Check for opens in the 5 volt reference circuit .

Test Description

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

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

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

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 one at a time, including the PCM while checking for continuity on that circuit to chassis ground.

Step

Action

Value(s)

Yes

Important: Before clearing any DTCs, use the scan tool Capture Info to save freeze frame and failure records for reference, as the scan tool loses data when using the Clear Info function.

Was the Powertrain On-Board Diagnostic (OBD) System Check performed?

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

Connect a scan tool.
Start the engine and let the engine idle.
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

Turn the ignition OFF.
Disconnect the boost sensor electrical connector.
Jumper the boost sensor 5 volt reference to the boost sensor signal circuit at the harness.
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

Turn the ignition OFF.
The boost sensor is still disconnected.
Remove the jumper wire.
Jumper the boost sensor signal circuit at the harness with a test light connected to B+.
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

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

Are there any additional DTCs stored?

Go to the Applicable DTC Table

Go to Diagnostic Aids

Check for a poor connection at the boost sensor.
If a problem is found, repair the problem as necessary.

Was a problem found?

Go to Step 13

Go to Step 10

Check for the following in the boost sensor signal circuit.

•	For an open

•	For a short to ground

If a problem is found, repair as necessary.

Was a problem found?

Go to Step 13

Go to Step 11

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

Was a problem found?

Go to Step 13

Go to Step 9

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

Was a problem found?

Go to Step 13

Go to Step 12

Replace the Boost sensor. Refer to Boost Sensor Replacement .

Is the action complete?

Go to Step 13

Check the terminal connectors at the PCM for a poor connection.
If a problem is found, repair the problem as necessary.

Was a problem found?

Go to Step 13

Go to Step 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

Using the scan tool, clear the DTCs.
Start engine and idle at normal operating temperature.
Select DTC, Specific, then enter the DTC number which was set.
Operate the vehicle, within the Conditions 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

Does the scan tool display any additional undiagnosed DTCs?

Go to the Applicable DTC Table

System OK