G46610 Dubai · Mercedes GlE · Black

# DIAGNOSTIC PLAN DRAFT — Mercedes GLE, VIN 4JGFD8KB6SB288041

## 1) SYMPTOM SUMMARY
Customer complaint is generic — "air in suspension" — with technician's note "putting air in suspension," suggesting the air suspension (AIRMATIC/ECAS) system is losing ride height and someone has been manually topping it up rather than diagnosing the leak or fault source. No mileage recorded, no comeback flagged. This needs a proper root-cause workup before any part (compressor, air spring/bellows, valve block) is ordered.
**ملخص:** الشكوى «هواء في التعليق» — يبدو أن أحداً كان يضخّ هواء يدوياً بدل تشخيص سبب الفقدان؛ لا بيانات كافية بعد.

## 2) LIKELY CAUSES (ranked)
1. **Air spring (bellows) leak** — most common cause of a corner sagging / repeated "topping up," especially with age/UV/rubber fatigue.
2. **Air suspension compressor relay/fuse or compressor unit fault** — compressor runs excessively or fails to build pressure, ECU logs low-pressure fault.
3. **Leaking air line / connector / valve block (solenoid valve seal)** — slow leak at fittings under the vehicle or valve block, often intermittent.
4. **Ride height sensor fault or miscalibration** — system reads wrong height and over/under-inflates one corner even without a real leak.
5. **Air suspension ECU/control module fault** — least likely; only consider after wiring, sensors, valves, and mechanical leaks are ruled out.
**ملخص:** الاحتمالات الأرجح مرتبة: تسرب كيس الهواء ← الكمبروسر/الريلاي ← تسرب خط/صمام ← حساس ارتفاع ← وحدة تحكم (الأقل احتمالاً).

## 3) TEST SEQUENCE (cheapest first)

1. **Customer/visual interview + walk-around (free).** Ask: does it sag overnight, at one corner, or all four? Does the compressor run constantly or cycle on ignition/door open? Any warning lamp? Visually compare ride height corner-to-corner by eye.
   - Expected: identifies pattern (single corner = spring/line leak likely; all corners + compressor running a lot = compressor/valve block or system-wide leak).
   - If unclear → step 2.

2. **Autel VID (Auto Detect/VIN scan) → Auto Scan (Topology or List tab)** on the full vehicle, targeting the Suspension/Level Control (AIRMATIC/ECAS) module. Record all DTCs and check **Freeze Frame** before touching anything.
   - Expected: fault code(s) pointing to a specific corner, low pressure, sensor circuit, or compressor.
   - If no codes → step 3 anyway (codes aren't always set for slow leaks).

3. **Control Unit > Live Data** on the suspension module: ride height sensor values (all 4 corners), compressor run status, valve commanded state, system air pressure PID if available. Use **Trigger Settings** to catch an intermittent low corner while idling/driving, and **Graph Merge** to compare all 4 corner heights on one graph.
   - Expected: one corner reading lower/drifting vs the others, or compressor cycling abnormally.
   - If a corner is confirmed low with no DTC explanation → step 4.

4. **Soap-water leak test (cheap, non-destructive)** on the suspect corner: air spring bellows folds, all visible air line fittings, and valve block, with the system pressurized (compressor running or via Active Test in step 5). Also inspect for chafed/pinched lines.
   - Expected: bubbles pinpoint the exact leak location.
   - If leak found at bellows → root cause confirmed, air spring replacement justified. If no visible leak → step 5.

5. **Autel Active Test** on the suspension module: command the compressor ON and each corner's solenoid valve individually while watching Live Data (pressure/height response) and listening/feeling for airflow at the valve block and lines.
   - Expected: compressor builds pressure normally, each valve audibly actuates and the commanded corner responds in Live Data.
   - If compressor fails to build pressure or a valve doesn't respond electrically → step 6. If compressor/valves test OK but corner still won't hold air → the leak is downstream (air spring or line), root cause is mechanical — proceed to part replacement per the confirmed leak point.

6. **Multimeter voltage & voltage-drop test** at the compressor relay/fuse and compressor ground, under load (compressor commanded on via Active Test), to distinguish a wiring/relay/ground fault from a genuinely failed compressor.
   - Expected: supply voltage present, no significant voltage drop across relay/ground.
   - If voltage/ground is good but compressor still doesn't run/build pressure → compressor unit itself is the root cause. If voltage drop found → repair wiring/relay/ground, not the compressor.

7. **If steps 2–6 show no fault and no visible leak:** a pressure leak-down/hold test per **TOPIx/ALLDATA procedure for this VIN** is needed (isolating each corner and monitoring pressure decay over time) — this is the escalation step before condemning any component.

**ملخص التسلسل:** نبدأ بالفحص البصري المجاني، ثم قراءة الأعطال والبيانات الحية بالأوتيل، ثم اختبار الصابون لتحديد التسرب، ثم Active Test لعزل الصمام/الكمبروسر، ثم الملتيميتر للكهرباء — كل خطوة تحدد التالية.

## 4) DATA TO COLLECT
- All DTCs from Auto Scan + full Freeze Frame data (record before any code is cleared).
- Live Data snapshot: ride height per corner (FL/FR/RL/RR), compressor run status, valve commanded vs actual state, system pressure PID (if present).
- Result of soap-water test: exact leak location + photo (attach to Pre-Scan/DVI record).
- Active Test results per valve/compressor: response observed (audible click, airflow, height change) — pass/fail per corner.
- Multimeter readings: supply voltage at compressor connector, voltage drop across relay contacts and ground path under load — **get the exact spec/tolerance from TOPIx/ALLDATA for this VIN** before judging pass/fail.
- Battery voltage during compressor operation (low battery can mimic a compressor fault).
**ملخص:** سجّل الأكواد وFreeze Frame، قيم الارتفاع لكل زاوية، نتيجة اختبار الصابون بالصور، نتائج Active Test، وقراءات الملتيميتر — والمواصفة الدقيقة من TOPIx/ALLDATA حسب الشاصي.

## 5) SAFETY
- **Lifting:** confirm the correct jacking/lifting procedure for an air-suspension Mercedes in TOPIx/ALLDATA before raising the vehicle — some models require the suspension to be placed in a locked/transport mode first to prevent the compressor cycling or a corner dropping unexpectedly while on the lift or jack stands. Do not work under a vehicle supported only by the air suspension itself.
**ملخص السلامة:** تحقق من إجراء الرفع الصحيح لسيارة بتعليق هوائي من TOPIx/ALLDATA قبل الرفع — بعض الموديلات تحتاج قفل النظام أولاً لمنع هبوط مفاجئ.

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DRAFT — the technician must verify before any part is ordered. مسودة — القرار النهائي للفني.