GM Service Manual Online
For 1990-2009 cars only

Object Number: 475481  Size: SF
Engine Controls Components
IAC Valve, MAF and Knock Sensors
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The PCM contains integrated Knock Sensor (KS) diagnostic circuitry. Input signals from the knock sensors are used to detect engine detonation, allowing the PCM to retard Ignition Control (IC) spark timing based on the amplitude and frequency of the KS signal being received. The knock sensors produce an AC signal under all engine operating conditions. During engine operation, the PCM calculates the average voltage of each knock sensor's signal. If the knock sensor system is operating normally, the PCM should monitor KS signal voltages varying over 0.5 volt above and below the calculated average voltage. If the PCM detects a Knock Sensor 2 signal voltage within the calculated average voltage range, DTC P0332 will set.

Conditions for Running the DTC

    • No TP sensor, VSS, CKP, MAF or ECT sensor DTCs set.
    • The engine coolant temperature is more than 75°C (167°F).
    • The throttle angle is more than 3 percent.
    • The engine load is more than 20 percent.
    • The engine speed is between 1000-4000 RPM.
    • The maximum system spark retard is less than 15 degrees.
    • The system voltage is more than 9 volts.

Conditions for Setting the DTC

The PCM detects a knock sensor 2 signal voltage within the calculated average range.

Action Taken When the DTC Sets

    • The PCM will not illuminate the malfunction indicator lamp (MIL).
    • The PCM will store the conditions that were present when the DTC set as Fail Records data only. This information will not be stored as Freeze Frame data.
    • The PCM will use a calculated spark retard value to minimize knock during conditions wunder which knock is likely to occur. The calculated value will vary based on the engine speed and load.

Conditions for Clearing the MIL/DTC

    • A history DTC P0332 will clear after 40 consecutive warm-up cycles have occurred without a fault.
    • DTC P0332 can be cleared by using the scan tool Clear Information function or by disconnecting the PCM battery feed.

Diagnostic Aids

Check the following components and conditions:

    • A faulty connection at the PCM or knock sensor 2--Inspect knock sensor 2 and the PCM connectors for backed out terminals, broken locks, and improperly formed or damaged terminals. Use a corresponding mating terminal to check for proper terminal tension.
    • A misrouted harness--Inspect the knock sensor harness to ensure that it is not routed too close to high voltage wires such as spark plug leads.

Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition occurs that caused the DTC to set. This may assist in diagnosing the condition.

Test Description

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

  1. Ensures that the malfunction is present.

  2. Checks for a false knock signal caused by a malfunctioning knock sensor.

  3. Ensures that the knock sensor is capable of producing a correct AC signal.

  4. This vehicle is equipped with a PCM that utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is replaced, the new PCM must be programmed.

DTC P0332 - Knock Sensor Circuit Bank #2

Step

Action

Value(s)

Yes

No

1

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

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2

Important: If an engine knock can be heard, repair the engine mechanical problem before proceeding with this diagnostic. Refer to Engine Noise Diagnosis in Engine Mechanical.

  1. Operate the engine within conditions specified in Conditions for Setting the DTC.
  2. Using a scan tool, monitor Specific DTC info for DTC P0332 until the DTC P0332 test runs.

Does scan tool indicate DTC P0332 failed this ignition?

--

Go to Step 4

Go to Step 3

3

  1. Turn ON the ignition switch, engine not running.
  2. Review and record scan tool Fail Records data for DTC P0332.
  3. Operate vehicle within Fail Records conditions.
  4. Using a scan tool, monitor Specific DTC info for DTC P0332 until the DTC P0332 test runs.

Does the scan tool indicate DTC P0332 failed this ignition?

--

Go to Step 4

Go to Diagnostic Aids

4

  1. Turn ON the ignition switch, engine not running.
  2. Disconnect the bank #2 knock sensor electrical connector.
  3. Using a DMM, measure voltage between the bank #2 KS signal circuit and ground.

Does the DMM indicate voltage at the specified value for the bank #2 knock sensor?

0V

Go to Step 5

Go to Step 8

5

  1. Connect the DMM to measure voltage between the Bank 2 knock sensor terminal and engine ground.
  2. Select 2 volts AC scale on the DMM.
  3. Engine idling, observe the DMM.

Is any signal indicated on the DMM for the bank #2 knock sensor?

--

Go to Step 9

Go to Step 6

6

  1. Turn OFF the ignition switch.
  2. DMM still connected to measure voltage between the bank #2 knock sensor terminal and engine ground.
  3. Tap on the engine lift bracket while observing the DMM.

Is any signal indicated on the DMM while tapping on the engine lift bracket?

--

Go to Step 7

Go to Step 9

7

  1. Check the bank #2 KS signal circuit for incorrect routing near secondary wires or for a poor terminal connection at the knock sensor.
  2. If a problem is found, repair as necessary.

Was a problem found?

--

Go to Step 12

Go to Step 10

8

  1. Turn OFF the ignition.
  2. Disconnect the PCM.
  3. Turn ON the ignition.
  4. Check the bank #2 KS signal circuit between the PCM and the knock sensor connector for the following conditions:
  5. • An open
    • A short to voltage
    • A short to ground
  6. If a problem is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a problem found?

--

Go to Step 12

Go to Step 10

9

Replace the bank #2 knock sensor. Refer to Knock Sensor Replacement - Bank 2 .

Is the action complete?

--

Go to Step 12

--

10

  1. Turn OFF the ignition switch.
  2. Disconnect the PCM.
  3. Check the bank #2 KS signal circuit for a poor terminal connection at the PCM.
  4. If a problem is found, repair as necessary.

Was a problem found?

--

Go to Step 12

Go to Step 11

11

Important:: The replacement PCM must be programmed.

Replace the PCM. Refer to Powertrain Control Module Replacement/Programming

Is the action complete?

--

Go to Step 12

--

12

  1. Review and record Fail Records data
  2. Clear the DTCs.
  3. Operate the vehicle within the Fail Records conditions.
  4. Using a scan tool, monitor the Specific DTC information for DTC P0332 until the DTC P0332 test runs.

Does the scan tool indicate DTC P0332 failed this ignition?

--

Go to Step 2

System OK