P1683

Code

MINI P — Powertrain

Electronic throttle control monitor level 2/3 - idle speed 'b' calculation fault

Brand: MINI

Type: P — Powertrain

Views: UK: 2 EN: 10 RU: 3

AI status

Completed

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Page language: EN

Causes

Dirty or sticking throttle body/throttle plate
Faulty throttle actuator/motor or internal throttle body electronics
Incorrect or noisy throttle position sensor (TPS) or accelerator pedal position sensor (APPS) signals
Wiring harness damage, poor connector contacts or corrosion at throttle body or ECU
Low or unstable battery/charging system voltage
Faulty mass air flow (MAF), engine coolant temperature (ECT) sensor or other inputs used for idle calculation

Symptoms

Check Engine Light (MIL) illuminated
Unstable idle speed, rough idle, or engine stalling at idle
High or low idle RPM
Reduced throttle response or limp-home mode
Occasional or persistent idle surges or hunting

What to check

Read freeze frame and full scan tool data; record other stored codes
Check battery voltage and charging system under load (should be ~12.6V key off, 13.5–14.8V running)
Visual inspection of throttle body connector and wiring for damage, corrosion or loose pins
Scan live data: actual throttle plate angle, requested throttle angle, idle target, engine RPM, APPS values, MAF, ECT
Check for vacuum leaks (hoses, intake manifold gaskets)
Check for available ECU software updates and documented service bulletins

Signal parameters

Throttle actual angle (degrees or %) — compares actual vs requested
Throttle requested/target angle (degrees or %)
Engine RPM and idle speed target
Accelerator pedal position sensor (APPS) values (all channels)
Mass airflow (MAF) or air flow rate
Engine coolant temperature (ECT)

Diagnostic algorithm

Retrieve DTCs and freeze frame data with a capable scan tool. Note the conditions when the fault set (temperature, RPM, load).
Verify battery and charging system health. Low or fluctuating voltage can cause throttle control errors.
Perform a visual inspection of throttle body wiring and connectors. Repair any damaged wires or corroded pins.
With the engine off, inspect and clean the throttle body and throttle plate if contamination or carbon buildup is present. Recheck for mechanical free movement.
Using a scan tool, monitor live data: compare requested throttle angle to actual throttle angle and check APPS-to-throttle correlation. Look for stuck, lagging, or inconsistent signals.
Run manufacturer-specific actuator tests (command throttle to several positions) and observe response and motor current. If the throttle does not follow commands or shows excessive current, suspect the throttle actuator or internal electronics.
Check supporting sensors used for idle calculation (MAF, ECT). Verify values are within expected ranges and correlate with ambient conditions.
Perform a pressure/vacuum leak test if idle is unstable and sensor data appears correct.
If wiring and mechanical systems are good, perform ECU/throttle body relearn/adaptation per manufacturer procedure. Clear codes and attempt to reproduce.
If fault persists, consider replacing the throttle body assembly or throttle actuator. After replacement, perform required adaptation and recheck system operation.
If failures continue after parts replacement, investigate ECU software level and consider reflashing or replacing the ECU following factory guidance.

Likely causes

Contaminated throttle body causing throttle plate to stick and invalid idle calculation
Intermittent wiring/connector fault between throttle body and ECU
Throttle actuator degradation causing mismatch between requested and actual throttle angle
Sensor input (MAF, ECT) producing incorrect values used in idle algorithm
Vehicle needs throttle/idle adaptation or ECU software update

Fault status

⚠️ Status

Electronic throttle control monitor level 2/3 — idle speed 'b' calculation invalid or mismatch. Fault logged when idle calculation/monitoring values are out of expected range or inconsistent with throttle/sensor inputs.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.5-3 hours

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P1683 — Electronic throttle control monitor level 2/3 - idle speed 'b' calculation fault