GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Isuzu 🢒 2001 🢒 Isuzu T-Series (Truck Line C) 🢒 Engine 🢒 Engine Controls - 7.8L 🢒 DTC 0032

Circuit Description

The boost pressure sensor is fixed on the cab back frame and is connected to the intake manifold by a vacuum hose.

The boost pressure sensor generates voltage according to air pressure and the generated voltage is input to the engine control module (ECM) for the boost sensor signal.

The ECM monitors the boost pressure sensor signals for voltage outside the normal range of the boost pressure sensor. If the ECM detects a boost pressure sensor signal voltage that is excessively low, DTC 0032 will be set.

Conditions for Setting the DTC
    • When the engine stalls and the relative boost pressure is higher than 20 kPa (2.9 psi) for 1 second or more.
    • The relative boost pressure is lower than -32 kPa (-4.6 psi) for 1 second or more.

Action Taken When the DTC Sets
    • Condition for setting the DTC is based on the relative pressure of 0 kPa (0 psi).
    • Condition for setting the DTC Injection amount map is used for a fail-safe mode.

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.

DTC 0032 can be cleared by using the Clear Info on the scan tool or by using the Diag Clear Switch.

Diagnostic Aids

Inspect for the following conditions:

    • Poor connection at the ECM
        Inspect harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal-to-wire connection.
    • Damaged harness
        Inspect the wiring harness for damage, shorts to ground, shorts to battery, and open circuits. If the harness appears to be OK, observe the boost pressure display on the scan tool while moving connectors and wiring harnesses related to the boost pressure sensor. A change in the boost pressure scan tool display will indicate the location of the fault.
    • Lack of power due to injection limitation.

Pressure

Voltage (V)

0 kPa (0 psi)

1.029

50 kPa (7.25 psi)

1.75

162 kPa (23.5 psi)

3.43

Step

Action

Value

Yes

No

Schematic Reference: Engine Controls Schematics

1

Does DTC 0032 set while the ignition ON or the engine is running?

--

Go to Step 2

Go to Diagnostic Aids

2
  1. Turn ON the ignition.
  2. Measure the voltage between pin number 61 and pin number 56 of the ECM harness connector C2.

Does the voltage measure near the specified value?

1.3 V

Go to Step 8

Go to Step 3

3

Measure voltage between pin number 72 and pin number 56 of the ECM harness connector C2.

Does the voltage measure within the specified range?

4.75-5.25 V

Go to Step 6

Go to Step 4

4
  1. Turn OFF the ignition.
  2. Disconnect boost sensor harness connector and the ECM harness connector.
  3. Measure the resistance between the following points on the harness:
    4. • Between pin number 72 at the ECM connector C2 and pin number 1 at the sensor connector
    • Between pin number 56 at the ECM connector C2 and pin number 3 at the sensor connector

Does each resistance measure less than the specified value?

2 ohms

Go to Step 5

Go to Step 12

5

Measure the resistance of the following points on the boost sensor harness:

    • Between pin number 72 of the ECM connector C2 and a good ground
    • Between pin number 56 of the ECM connector C2 and a good ground

Does each resistance measure more than the specified value?

10 M ohms

Go to Step 11

Go to Step 12

6
  1. Turn OFF the ignition.
  2. Disconnect the harness connector from the boost sensor and ECM.
  3. Measure resistance between the following points on the harness:
    4. • Between pin number 61 of the ECM connector C2 and pin number 3 of the sensor connector
    • Between pin number 56 of the ECM connector C2 and pin number 2 of the sensor connector

Does each resistance measure less than the specified value?

2 ohms

Go to Step 7

Go to Step 12

7

Measure resistance between the following points on the boost sensor harness:

    • Between pin number 61 of the ECM connector C2 and a good ground
    • Between pin number 56 of the ECM connector C2 and a good ground

Does each resistance measure more than the specified value?

10 M ohms

Go to Step 11

Go to Step 12

8
  1. Connect a pressure gage to the boost pressure sensor.
  2. Supply pressure.

Is voltage created to meet boost pressure?

--

Go to Step 9

Go to Step 11

9
  1. Reconnect all connectors.
  2. Start the engine.
  3. Operate the vehicle several times.

Are there any abnormal boost pressure voltages or any leakage?

--

Go to Step 10

Go to Step 13

10

Inspect the turbocharger condition, waste gate opening pressure, and/or piping.

Is the opening pressure of the waste gate correct?

 

System OK

Go to Step 15

11

Replace the boost pressure sensor.

Did you complete the replacement?

--

Go to Step 13

--

12

Repair the boost pressure sensor wiring harness.

Did you complete the repair?

--

Go to Step 13

--

13

Clear all DTCs.

Does DTC 0032 reset?

--

Go to Step 14

System OK

14

Replace the ECM. Refer to Engine Control Module Replacement/Restore Fuel Rate Data .

Did you complete the replacement?

Go to Step 16

--

15

Repair piping and/or readjust the waste gate opening pressure.

Did you complete the repair?

--

Go to Step 16

--

16
  1. Clear the DTCs.
  2. Operate the vehicle in the Conditions for Running the DTC.

Does DTC 0032 reset?

 

Go to Step 2

System OK