B1600 – PATS Ignition Key Transponder Signal Is Not Received: Symptoms, Causes, Diagnosis & Repair Cost (2026 Guide)

B1600

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Overview

The control module stored B1600 because it detected a problem with: PATS Ignition Key Transponder Signal Is Not Received.

B1600 relates to PATS Ignition Key Transponder Signal Is Not Received. Use a quality scan tool, follow wiring diagrams for your vehicle, and confirm tests before replacing expensive parts.

What does the B1600 code mean?

When B1600 is set, the vehicle’s diagnostics detected an issue described as: PATS Ignition Key Transponder Signal Is Not Received. In practice, the ECM/PCM (and related modules) compare sensor inputs, commanded outputs, and self-tests for that subsystem. The exact repair depends on whether the fault is wiring-related, component-related, or a rationality/performance issue for this circuit or system.

Common symptoms of B1600

  • Hard start
  • Check engine light
  • Flashing MIL under load
  • Poor fuel economy
  • Misfire felt at idle or load
  • Power loss

Possible causes

  • Fault affecting PATS Ignition Key Transponder Signal Is Not Received (wiring, connector, or component)
  • Control module strategy or calibration issue
  • Electrical fault in the monitored circuit
  • Component failure in the described system
  • Control module or software calibration issue (less common—verify tests first)
  • Past repairs or aftermarket parts causing out-of-spec operation

How to diagnose B1600

  1. Scan for B1600 and review freeze frame / pending codes for related faults
  2. Inspect connectors and wiring related to: PATS Ignition Key Transponder Signal Is Not Received
  3. Compare live data and commanded vs actual values for the affected system (per service information)
  4. Perform circuit tests appropriate to the fault type (continuity, voltage, resistance) before replacing parts
  5. Confirm power and ground integrity at the relevant module or sensor
  6. After repair, clear DTCs and verify under the conditions that originally set B1600

Tip: Use a scan tool that shows live data and freeze frame for the conditions when the code set.

Severity of code B1600

Moderate: Have this code diagnosed soon; ignoring it can lead to worse fuel economy, repeat failures, or secondary damage.

Can you drive with B1600?

Short trips may be okay if the vehicle feels normal, but have it diagnosed—especially if performance, safety warnings, or overheating are present.

Avoid heavy acceleration, towing, or long highway drives until the cause of B1600 is confirmed and repaired.

How to fix it (step-by-step)

  1. Start with visual inspection and connector cleaning/tightening where needed
  2. Confirm failure mode with testing—avoid swapping parts without evidence
  3. Repair wiring or replace the failed component per manufacturer procedure
  4. Clear faults, run relearns if required, and road test to confirm

Repair & fix options

  • Inspect connectors and wiring first
  • Test component against service limits
  • Clear codes and verify with drive cycle
  • Clear codes and verify repair with a drive cycle and readiness where applicable
  • Reinspect related monitors if the code returns after repair

Typical repair cost

$100 – $2,000+ depending on cause

Estimated cost breakdown for B1600
Repair type Typical range
Diagnostic And Minor $120 – $650
Common Component Work $100 – $500
Major Subsystem Repair $250 – $1,200
Severe Or Replacement $500 – $2,000+

How to help prevent B1600 in the future

  • Fix new codes early before secondary damage or catalyst stress
  • Keep connectors clean and secure; address rodent or water intrusion in harnesses
  • Use the correct fluids/parts for your vehicle and service intervals
  • Avoid ignoring pending codes after battery work or repairs

When to see a mechanic

Schedule diagnosis if the check engine light is on, drivability is worse, or you notice new noises, smells, or warning lamps. For safety-related (SRS/ABS) or overheating symptoms, prioritize a qualified shop immediately.

Common mistakes when diagnosing B1600

  • Replacing sensors/modules without verifying wiring and reference voltages
  • Ignoring related codes that identify the real root cause
  • Clearing codes without a verification drive cycle

Common vehicles & notes for B1600

  • Volkswagen / BMW models (common examples—verify for your vehicle)
  • Mercedes-Benz / Audi applications vary by engine and model year
  • Many other makes—this is a standardized OBD-II definition: PATS Ignition Key Transponder Signal Is Not Received

B1600 is reported across many platforms including Volkswagen, BMW, Mercedes-Benz, Audi. Always use VIN-specific service information for testing limits and calibration steps.

Frequently asked questions

What does B1600 mean?

B1600 indicates a fault involving PATS Ignition Key Transponder Signal Is Not Received, based on what the control module detected during self-tests or live monitoring.

Is it safe to drive with B1600?

If the vehicle runs normally and no warning lights are flashing, short trips may be reasonable—but avoid ignoring symptoms like misfire, overheating, ABS/SRS warnings, or major loss of power.

How much does it cost to fix B1600?

Typical repairs often fall in the ranges shown on this page, but final cost depends on labor rate, parts quality, and whether the issue is wiring vs. a major component.

What is the most common cause of B1600?

Most shops start with wiring/connectors and the directly monitored component for “PATS Ignition Key Transponder Signal Is Not Received,” then expand testing if the fault returns.

Will B1600 clear itself?

It may become intermittent, but if the underlying fault remains, the code will usually return—especially after a drive cycle.

Can a weak battery cause B1600?

Low system voltage can cause odd sensor/module behavior, but you should still validate the actual DTC and perform normal circuit/component tests.

Related tools

This information is for educational purposes only and is not a substitute for hands-on diagnosis. Always follow manufacturer service information and consult a qualified automotive technician for repairs.