Ignition System Crankshaft Position Sensor Diagnosis. Oldsmobile Shelby Series 1 1999

For 1990-2009 cars

Refer to engine controls schematics
Engine Controls Components
Ignition Control Module
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice
.

### Circuit Description

This diagnostic test checks for 24X signal at a logic high condition. The fault could be induced by the failure of either crankshaft position (CKP) A or B sensor input signal to the ignition control module (ICM).

### Test Description

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

1. This step is checking for a faulty crank A sensor or circuit failure.

2. This step is checking for a faulty crank B sensor or circuit failure.

3. To ensure acuurate voltage readings, connect the DMM to the sensor before recording the Peak Min Max voltage.

4. To ensure acuurate voltage readings, connect the DMM to the sensor before recording the Peak Min Max voltage.

5. A diagnostic jumper can be created with the terminals supplied in the J 38125-A terminal repair kit. Assemble the jumpers and terminals and cover the exposed terminals with heat shrink tubing. Do not cover the spade of the male terminals.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | 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. Turn the key to OFF.
2. Disconnect ICM connector C1.
3. Using the DMM, measure the resistance between the harness side of the connector terminals A and B.

Is the resistance between the range specified?

800-1,600 ohms

Go to Step 3

Go to Step 10

3 | Measure the resistance between connector terminals E and F. Is the resistance between the range specified? | 800-1,600 ohms | Go to Step 2 | Go to Step 13
4 | Measure the resistance to ground at ICM connector C1 terminals A then B then E and then F. Is the resistance at any terminal less than the value specified? | 1,000 ohms | Go to Step 16 | Go to Step 5

5

1. Disconnect ICM connector C2 to disable ignition.
2. Set DMM to peak min/max, 4 volt scale, 1 ms sampling rate.
3. Measure the max DC voltage across IC module connector C1 terminals A and B.
4. Crank the engine for 10 seconds.

Is the voltage measured while cranking more than the value specified?

0.25 volts

Go to Step 6

Go to Step 18

6

1. Set DMM to peak min/max, 4 volt scale, 1 ms sampling rate.
2. Measure the max DC voltage across ICM connector C1 terminals E and F.
3. Crank the engine for 10 seconds.

Is the voltage measured while cranking more than the value specified?

0.25 volts

Go to Step 7

Go to Step 19

7

1. Reconnect ICM connectors C1 and C2.
2. Disconnect ICM connector C4.
3. Turn the key ON.
4. Measure the voltage to ground at PCM connector C1 terminal 16.

Is the voltage less than the value specified?

0.4 volts

Go to Step 8

Go to Step 17

8

1. Turn the key to OFF.
2. Reconnect PCM connector C1.
3. Install a diagnostic jumper at ICM connector C4.

OR:

• | Jumper C4 terminal A to module pin A.

• | Jumper C4 terminal B to module pin B.

• | Jumper C4 terminal C to module pin C.

• | Jumper C4 terminal D to module pin D.

• | Jumper C4 terminal E to module pin E.

• | Jumper C4 terminal F to module pin F.

4. Connect the DMM between jumper A and ground keeping the DMM leads away from the ICM, ignition coils, and secondary ignition wires.
5. Set the DMM to 4V D/C scale and push the Hz button.
6. Crank the engine.

Does the FREQUENCY measure more than the value specified?

0 Hz

Go to Step 9

Go to Step 24

9

1. Remove just the terminal A jumper.
2. Start the engine.
3. Using a scan tool select DTC Information.

Has DTC P1323 Failed This Ign.?

--

Go to Diagnostic Aids

Go to Step 26

10 | Was the resistance lower in Step 2 than the range that was specified? | -- | Go to Step 11 | Go to Step 12

11

1. Disconnect crank sensor A connector at sensor.
2. Measure resistance across terminals A and B at the harness side of the sensor connector.

Is the resistance lower than the value specified?

10,000 ohms

Go to Step 20

Go to Step 18

12

1. Disconnect crank sensor A connector at sensor.
2. Jumper terminals A and B together at the harness side of the sensor connector.
3. Measure the resistance across ICM connector C1 terminals A and B.

Is the resistance more than the value specified?

5 ohms

Go to Step 21

Go to Step 18

13 | Was the resistance lower in step 3 than the range that was specified? | -- | Go to Step 14 | Go to Step 15

14

1. Disconnect crank sensor B connector at sensor.
2. Measure resistance across terminals A and B at the harness side of the sensor connector.

Is the resistance lower than the value specified?

10,000 ohms

Go to Step 22

Go to Step 19

15

1. Disconnect crank sensor B connector at sensor.
2. Jumper terminals A and B together at the harness side of the sensor connector.
3. Measure the resistance across ICM connector C1 terminals E and F.

Is the resistance more than the value specified?

5 ohms

Go to Step 23

Go to Step 19

16 | Repair the short to ground in the circuits that measured low in step 4. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 28 | --
17 | Repair the short to voltage on the 24X spark reference circuit. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 28 | --
18 | Replace crank sensor A. Refer to Crankshaft Position Sensor Replacement . Is the repair complete? | -- | Go to Step 28 | --
19 | Replace crank sensor B. Refer to Crankshaft Position Sensor Replacement . Is the repair complete? | -- | Go to Step 28 | --
20 | Repair the crank A high circuit and the crank A low circuit shorted together. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 28 | --
21 | Repair the open or short in the crank A high circuit and/or the crank A low circuit. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 28 | --
22 | Repair the crank B low circuit and the crank B high circuit shorted together. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 28 | --
23 | Repair the open or short in the crank B low circuit and/or the crank B high circuit. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 28 | --

24

1. Check terminal contact at the ICM connector C1 terminals A, B, E and F.
2. Repair terminal contact if needed. Refer to Connector Repairs in Wiring Systems.

Was terminal contact repaired?

--

Go to Step 24

Go to Step 25

25 | Replace the ICM. Refer to Ignition Control Module Replacement . Is the replacement complete? | -- | Go to Step 28 | --

26

1. Check terminal contact at the PCM connector C1 terminal 16.
2. Repair terminal contact if needed. Refer to Connector Repairs in Wiring Systems.

Was terminal contact repaired?

--

Go to Step 28

Go to Step 27

27 | Important: The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Is the replacement complete? | -- | Go to Step 28 | --
28 | Select the Capture Info option and the Review Info option using the scan tool. Does the scan tool display any DTCs that you have not diagnosed? | -- | Go to the applicable DTC table | System OK