P1602 — Powertrain Control Module Communication Line To TCM Error, Immobilizer System Communication Error With Powertrain Control Module

What Does P1602 Mean?

P1602 is a manufacturer-specific diagnostic trouble code: Powertrain Control Module Communication Line To TCM Error, Immobilizer System Communication Error With Powertrain Control Module. This code applies to MAZDA, BMW, VOLKSWAGEN, OTHER, BUICK vehicles. Unlike generic OBD-II codes, manufacturer-specific codes are defined by the vehicle maker and may only apply to certain makes and models.

Symptoms of P1602

⚠️ Check Engine Light (MIL) illuminated
⚠️ Powertrain Control Module Communication Line To TCM Error, Immobilizer System Communication Error With Powertrain Control Module not functioning as expected
⚠️ Related system may be in fail-safe mode
⚠️ Reduced engine performance

Common Causes

🔍 Faulty Powertrain Control Module Communication Line To TCM Error, Immobilizer System Communication Error With Powertrain Control Module
🔍 Wiring or connector issue in Powertrain Control Module Communication Line To TCM Error, Immobilizer System Communication Error With Powertrain Control Module circuit
🔍 Related mechanical or electrical fault
🔍 ECM/PCM issue (rare)

Frequently Asked Questions

What does P1602 mean?

P1602 indicates: Powertrain Control Module Communication Line To TCM Error, Immobilizer System Communication Error With Powertrain Control Module. The vehicle's computer has detected that the Powertrain Control Module Communication Line To TCM Error, Immobilizer System Communication Error With Powertrain Control Module is not operating within its expected parameters and stored this diagnostic trouble code.

Can I drive with code P1602?

You can drive short distances for essential trips, but schedule a diagnosis soon. Driving with P1602 for extended periods may cause additional problems.

How much does it cost to fix P1602?

Repair costs for P1602 typically range from $80 to $300, depending on the root cause. Simple wiring or connector repairs are on the lower end, while component replacement costs more. A proper diagnosis ($80–$150 at most shops) will identify the exact cause before committing to expensive parts.

What To Do Next

Possible Fixes

🔧 Inspect Powertrain Control Module Communication Line To TCM Error, Immobilizer System Communication Error With Powertrain Control Module and related wiring
🔧 Replace faulty Powertrain Control Module Communication Line To TCM Error, Immobilizer System Communication Error With Powertrain Control Module

1
Find your vehicle above
Click your make and model for real owner reports and common causes specific to your vehicle.
2
Check for recalls
Go to nhtsa.gov/recalls and enter your VIN. Free repairs if covered.
3
Get a professional diagnosis
A code alone doesn't identify the exact failed part. A diagnostic ($50–$150) pinpoints the root cause.

P1602: Powertrain Control Module Communication Line To TCM Error, Immobilizer System Communication Error With Powertrain Control Module