The McLaren 720S That Wouldn't Enter Track Mode: A AED 800 Fix for a AED 28,000 Quote

Track mode on a McLaren 720S transforms the car. Suspension drops, damping stiffens, throttle sharpens, transmission holds gears — the car goes from GT cruiser to track weapon at the press of a button.

When "Dynamic Mode Unavailable" appears and Track mode won't engage, the owner has a AED 280,000+ supercar that can only operate in Comfort and Sport. That's like buying a concert grand piano that only plays in one octave.

The Problem

Vehicle: 2019 McLaren 720S, 18,000 km Symptom: "Dynamic Mode Unavailable" message when selecting Track mode Behaviour:

• Comfort mode: normal operation
• Sport mode: normal operation
• Track mode: refuses to engage, error message displayed
• No other warning lights or faults evident
• Issue appeared gradually — initially intermittent (Track mode would engage on second or third attempt), then permanent

Owner's frustration: The car was purchased specifically for track days at Dubai Autodrome. Without Track mode, the full potential of the car is inaccessible.

The Dealer's Approach

The dealer diagnostic found:

• Fault code in the hydraulic suspension control module
• Recommended replacement of the proactive chassis control hydraulic actuator (one of two units)
• Additional recommendation: replacement of the suspension fluid reservoir

Quote: AED 28,000 (actuator AED 18,000 + reservoir AED 4,000 + labour AED 6,000)

The dealer's reasoning: the hydraulic suspension fault prevented the system from entering Track mode's lowest, stiffest setting.

What We Found

Step 1: Full Module Scan

We connected McLaren's diagnostic system and performed a complete module scan.

Findings:

• Proactive Chassis Control (PCC) module: one stored fault — "hydraulic pressure sensor signal intermittent"
• No other module faults
• No mechanical fault codes — the actuator itself was not reporting a failure

Key observation: The fault was with the pressure sensor signal, not the actuator. The dealer had jumped from "suspension fault" to "replace the actuator" without distinguishing between the sensor reading and the component itself.

Step 2: Live Data Analysis

We monitored the PCC system in real time while cycling through modes:

Comfort mode: Hydraulic pressure readings within normal parameters (both sides) Sport mode: Pressure increased as expected — both sides responded correctly Track mode request: System began to increase pressure toward Track mode targets — then aborted. Left-side pressure sensor reading became erratic (jumping between actual pressure and zero) at high pressure levels

Diagnosis narrowing: The hydraulic system was physically capable of reaching Track mode pressures. The sensor was providing corrupted readings at high pressure, causing the control module to abort the mode change as a safety measure.

Step 3: Sensor Investigation

We inspected the left hydraulic pressure sensor:

Finding: The sensor connector showed signs of brake fluid contamination. The McLaren PCC system uses a hydraulic fluid that is chemically similar to brake fluid. A micro-leak at the sensor seal had allowed fluid to weep onto the connector pins over time.

The contamination created variable resistance on the sensor signal wire — causing accurate readings at low pressure (where the signal is strong relative to the interference) but erratic readings at high pressure (where the interference-to-signal ratio increased).

Step 4: Root Cause

Root cause: A deteriorated O-ring seal on the hydraulic pressure sensor allowed microscopic fluid weepage onto the connector. Dubai's thermal cycling (hot days, cool A/C-chilled garage nights) accelerated the seal degradation and caused condensation that mixed with the hydraulic fluid residue, creating a conductive film on the connector pins.

Step 5: Repair

Actions:

1. Flushed PCC hydraulic system (fluid was due for replacement at this mileage anyway)
2. Replaced sensor O-ring seal (AED 45 — genuine McLaren)
3. Cleaned sensor connector with electrical contact cleaner
4. Applied dielectric grease to connector
5. Cleared fault codes and recalibrated PCC system

Total cost: AED 800 (fluid flush + seal + connector treatment + labour)

Step 6: Verification

Post-repair testing:

• Comfort mode: normal
• Sport mode: normal
• Track mode: engaged immediately, no errors
• Left-side pressure sensor: stable readings across full pressure range
• 30-minute dynamic test cycling all modes: zero faults

Owner drove to Dubai Autodrome the following weekend. Track mode performed flawlessly.

The Cost Comparison

| Approach | Cost | Outcome | |----------|------|---------| | Dealer (actuator + reservoir replacement) | AED 28,000 | Would have replaced working components; sensor seal issue would persist | | MotorMec (fluid flush + seal + clean) | AED 800 | Root cause addressed, full functionality restored | | Savings | AED 27,200 | 97.1% reduction |

Key Takeaways

• "Sensor signal intermittent" is not the same as "component failure" — A fault in the sensor reading doesn't mean the component the sensor monitors has failed. The dealer replaced an actuator that was working perfectly — because they didn't distinguish between the sensor and the component.

• Connector contamination causes more hydraulic faults than mechanical failure — Fluid weepage onto electrical connectors creates resistance that corrupts sensor signals. Before replacing expensive hydraulic components, always inspect the sensor and its connector.

• McLaren's PCC system aborts mode changes as a safety measure — When sensor data is unreliable, the system refuses to enter modes that require higher pressures. This is correct behaviour — it's protecting the car. The fix is to restore reliable sensor data, not to replace the hydraulic hardware.

• Thermal cycling in Dubai accelerates seal degradation — The 30-40°C daily temperature swing between outdoor parking and A/C-chilled garages causes repeated thermal expansion and contraction of rubber seals. This is especially relevant on high-precision systems like McLaren's hydraulic suspension.

• A AED 800 seal and clean resolved what was quoted as AED 28,000 in component replacements — Diagnostic precision matters. The cheapest fix is usually the correct one when the diagnosis is thorough enough.

Frequently Asked Questions

Q: Is the McLaren 720S hydraulic suspension reliable?

A: The PCC system is mechanically robust but requires maintenance attention — particularly fluid changes and seal inspections. In Dubai conditions, fluid should be changed every 3-4 years or 20,000-25,000 km. With proper maintenance, the system is reliable.

Q: Can other McLaren models have similar issues?

A: All McLaren models with the PCC hydraulic suspension (570S, 600LT, 720S, 765LT, GT, Artura) can experience similar sensor and seal issues. The system architecture is shared across the range.

Q: Do I need the McLaren diagnostic tool for this repair?

A: Yes — the PCC system requires McLaren's dedicated diagnostic tool for mode testing, pressure data reading, and system recalibration after fluid changes. Generic OBD2 scanners cannot access the PCC module.

Q: How do I prevent this issue?

A: PCC fluid change at manufacturer intervals (or Dubai-adjusted shorter intervals), annual inspection of sensor connectors, and application of dielectric grease to hydraulic system connectors during service.

Q: Is Track mode safe to use on Dubai roads?

A: Track mode significantly reduces ride height and stiffens suspension — it's designed for smooth circuits. Dubai road surfaces and speed bumps can damage the lowered bodywork and stress the suspension at Track mode settings. Use Track mode only on circuits (Dubai Autodrome, Yas Marina) or very smooth road surfaces.

The Supercar Wasn't Broken. It Was Confused.

A AED 45 O-ring and a clean connector restored AED 280,000 worth of supercar to full capability. The hydraulic actuator was never the problem. The sensor connector was. And the difference between those two diagnoses was AED 27,200.

Equipment. Knowledge. Patience. And the willingness to question the obvious answer.

No Fix, No Fee.

Reviewed by [Supercar Specialist], MotorMec Dubai. Last updated: February 2026