P1393 Code Saab – Complete Diagnostic

Meaning of P1393 in Saab

The P1393 code in Saab vehicles (primarily those using GM platforms) generally indicates:
“Crankshaft Position (CKP) System Variation Not Learned”

This code means that the engine control module (ECM) was unable to store the crankshaft position sensor variation values, which are essential for optimal operation.

Main Causes

1. Learning procedure not performed after replacing the CKP sensor or ECM
2. Crankshaft position sensor (CKP) failure
3. Electrical issues:

• Damaged wiring or corroded connectors
• Short circuit or open circuit

4. Mechanical problems:

• Damaged teeth on the flywheel
• Excessive crankshaft play

5. Power supply issue (incorrect voltage to the sensor)
6. ECM failure (less common)

Common Symptoms

• Difficulty starting (especially when hot)
• Unstable idle
• Noticeable power loss
• Intermittent stalling
• Check engine light on
• Possible increase in fuel consumption

Diagnostic Procedure

1. Basic Checks

• Read all present fault codes
• Check recent repair history
• Visually inspect the CKP sensor and its connector

2. CKP Sensor Testing

• Measure resistance (compare with specifications)
• Check signal with an oscilloscope
• Verify power supply voltage (typically 5V or 12V)

3. Wiring Inspection

• Check continuity between sensor and ECM
• Look for short circuits to ground
• Inspect intermediate connectors

4. Mechanical Check

• Examine the flywheel (damaged teeth)
• Check crankshaft play
• Verify sensor alignment

Recommended Solutions

1. Perform the learning procedure:

• Requires a compatible Saab diagnostic tool (Tech2 or equivalent)
• Follow the model-specific procedure

2. Replace the CKP sensor if faulty:

• Use recommended OEM parts
• Properly position the sensor (correct air gap)

3. Repair wiring:

• Replace damaged wires
• Clean corroded connectors

4. Replace the flywheel if teeth are damaged

Affected Saab Models

This code may appear on:

• Saab 9-3 (GM platform)
• Saab 9-5
• Other models using GM engines

Technical Note: On some Saab models, this code may be accompanied by P0335 or P0336 in case of serious issues with the CKP system.

Prevention

• Always perform the learning procedure after any intervention
• Use quality OEM sensors
• Regularly check wiring condition

If the problem persists after these checks, further analysis with a professional diagnostic tool may be necessary to examine live data from the CKP system.