1. Meaning of Code Cadillac P1393
The P1393 code on Cadillac indicates:
“Intermittent failure of the Camshaft Position (CMP) sensor circuit – Bank 1”
Immediate consequences:
- Illumination of the “Check Engine” light
- Possible engine performance limitation
- Risk of hard starting in cold weather
2. Affected Cadillac Models
| Model | Engine | Years | Critical Mileage |
|---|---|---|---|
| CTS | 3.6L V6 (LGX) | 2016-2023 | 80,000-130,000 km |
| Escalade | 6.2L V8 (L87) | 2021-2023 | 50,000-90,000 km |
| XT5 | 2.0L Turbo (LSY) | 2017-2023 | 60,000-100,000 km |
| ATS | 2.5L I4 (LCV) | 2013-2019 | 100,000-150,000 km |
3. Main Causes
A. Electrical Problems (75%)
- Faulty CMP sensor (GM P/N 12677925)
- Damaged wiring (critical area: engine harness passage)
- Corroded CMP connector (frequent oxidation)
- Unstable power supply (4.5-5.5V required)
B. Mechanical Problems (20%)
- Excessive camshaft play
- Metal deposits on the tone wheel
- Timing issue (chain/ring)
C. Other Causes (5%)
- Partial ECM failure
- Software requiring update
- Grounding issue (G110)
4. Diagnostic Procedure
Step 1 – Initial Checks
- Visual inspection of the sensor and connector
- Check oil level (5W-30 Dexos2)
- Search for associated codes (P0016, P0340)
Step 2 – Electrical Tests
| Test | Method | Normal Values |
|---|---|---|
| Power supply voltage | Ignition ON | 5V ±0.5V |
| CMP resistance | Sensor disconnected | 500-1500Ω |
| Signal | Oscilloscope | Stable square signal |
Step 3 – Advanced Checks
- Data analysis with GDS2 scanner
- Inspection of timing chain (3.6L)
- Check oil pressure (>25 psi)
5. Solutions by Engine
For 3.6L V6 (LGX)
- Replace CMP sensor (improved version)
- Inspect chain tensioner
- Clean ECM connector X1
For 6.2L V8 (L87)
- Check wiring near exhaust manifolds
- Inspect AFM/DoD system
- ECM software update
For 2.0L Turbo (LSY)
- Complete CMP circuit inspection
- Check turbo and oil lines
- Clean connectors
6. Key Technical Data
- Tightening torque: 10 Nm
- Sensor gap: 0.8-1.6mm
- Inspection interval: 100,000 km
7. Repair Costs
| Service | Cost (CAD) | Warranty |
|---|---|---|
| Sensor replacement | $200-400 | 2 years |
| Wiring repair | $300-600 | 1 year |
| Diagnostic | $100-180 | – |
8. Mistakes to Avoid
- Using non-OEM sensors
- Neglecting wiring inspection
- Forgetting to reset adaptations
9. Technical FAQ
Q: Risk to the engine?
→ Possible VVT damage if ignored
Q: Temporary driving possible?
→ Maximum 50 km at moderate RPM
Q: Difference with P0340?
→ P1393 = performance problem, P0340 = open circuit
10. Post-Repair Procedure
- Clear codes with GDS2
- Perform a break-in cycle:
- 20 min at 2000-2500 RPM
- 3 stop/starts
- Check CMP parameters
11. Prevention Tips
- Strict oil changes (max 10,000 km)
- Annual wiring inspection
- Use Dexos2 oil
- Clean connectors every 2 years
12. Conclusion
To resolve P1393 on Cadillac:
- Complete diagnostic with GDS2
- Thorough electrical verification
- Use GM Original parts
⚠ Important: Recurring problems often require a full engine harness inspection. Consult a certified Cadillac technician for complex cases.