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P2187AcuraAcura MDX HubAll Acura P2187Medium Severity

P2187 on Acura MDX

System Too Lean at Idle (Bank 1)

Factory diagnostic protocol and troubleshooting wire for fault code P2187 specifically for the Acura MDX (2022–2026, 3.5L i-VTEC V6 (290HP) / 3.0L Turbo V6 (Type S 355HP / SH-AWD)).

Verified OEM Telemetry & Field Repair Tree
Acura MDX2022–2026
Acura MDX
SUV3.5L i-VTEC V6 (290HP) / 3.0L Turbo V6 (Type S 355HP / SH-AWD)
Reliability
Sensor Voltage Ref
0.1V – 5.0V Ref
MDX SAE Mode $01
ECU Network Bus
500 kbps CAN-FD
ISO 15765-4 Compliant
Drivability Status
Drivable (Short Trip)
Medium urgency level
Est. Repair Cost
$120 - $480 (DIY: $35 - $150)
Parts & Labor DIY
Check P2187 On Another Acura Model:
Diagnose P2187 on Specific MDX Model Year:

1. Symptoms of P2187 on Acura MDX

When the Engine Control Module (ECM/PCM) on your Acura MDX (3.5L i-VTEC V6 (290HP) / 3.0L Turbo V6 (Type S 355HP / SH-AWD)) logs fault code P2187, drivers commonly observe:

Check Engine Light on on Acura MDX (3.5L i-VTEC V6 (290HP) / 3.0L Turbo V6 (Type S 355HP / SH-AWD))
Rough, erratic, or surging idle that smooths out once driving on Acura MDX (3.5L i-VTEC V6 (290HP) / 3.0L Turbo V6 (Type S 355HP / SH-AWD))
Hissing or whistling vacuum sound from engine bay at idle on Acura MDX (3.5L i-VTEC V6 (290HP) / 3.0L Turbo V6 (Type S 355HP / SH-AWD))
High Long Term Fuel Trim (+15% to +25%) only at idle RPM on Acura MDX (3.5L i-VTEC V6 (290HP) / 3.0L Turbo V6 (Type S 355HP / SH-AWD))
Acura MDX OBD-II Port Location
The 16-pin diagnostic connector is located Driver side lower dash assembly. Plug in your scan tool to verify freeze-frame sensor values.

2. Most Likely Causes on Acura MDX

Historical warranty claims and technical repair bulletins for Acura MDX point to the following failure distribution:

55%
Torn diaphragm in PCV valve / oil separator (common on VW/Audi 2.0T) (Acura OEM Part)
25%
Intake manifold gasket or vacuum hose leak (Acura OEM Part)
12%
Leaking oil dipstick O-ring or loose oil filler cap (Acura OEM Part)
8%
Faulty EVAP purge valve stuck slightly open (Acura OEM Part)
8%
Dirty or failing Mass Air Flow (MAF) sensor (Acura OEM Part)
* Source: Synthesized from NHTSA ODI field repair telemetry and verified OEM Technical Service Bulletin (TSB) repair tree frequency percentiles for Acura MDX.

3. Step-by-Step DIY Repair Guide for Acura MDX

01
Monitor Fuel Trims at Idle vs 2,500 RPM

Check STFT and LTFT. If trims are +20% at idle and drop to +3% at 2,500 RPM, a vacuum leak is 100% confirmed. on the Acura MDX equipped with 3.5L i-VTEC V6 (290HP) / 3.0L Turbo V6 (Type S 355HP / SH-AWD).

Required Tool: OBD-II Live Data Scanner
02
Perform Oil Cap Vacuum Test (PCV Check)

Try to remove oil filler cap while engine idles. If cap is held down with strong vacuum suction and engine whines, the PCV diaphragm is ruptured. on the Acura MDX equipped with 3.5L i-VTEC V6 (290HP) / 3.0L Turbo V6 (Type S 355HP / SH-AWD).

Required Tool: None
03
Smoke Test Intake & Vacuum Lines

Connect smoke machine to intake to identify leaking PCV hoses, manifold gaskets, or brake booster lines. on the Acura MDX equipped with 3.5L i-VTEC V6 (290HP) / 3.0L Turbo V6 (Type S 355HP / SH-AWD).

Required Tool: Automotive Smoke Machine
04
Replace Faulty PCV Assembly / Gaskets

Install a new OEM PCV oil separator assembly or replace cracked vacuum hoses. on the Acura MDX equipped with 3.5L i-VTEC V6 (290HP) / 3.0L Turbo V6 (Type S 355HP / SH-AWD).

Required Tool: Torx/Socket Set
05
Clear Trouble Codes

Clear DTCs and verify fuel trims return to ±5% at idle. on the Acura MDX equipped with 3.5L i-VTEC V6 (290HP) / 3.0L Turbo V6 (Type S 355HP / SH-AWD).

Required Tool: OBD-II Scanner
Recommended Parts & Testing Tools

Equipment for Diagnosing Acura MDX (P2187)

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Direct-Fit Replacement Part

Acura MDX OEM Replacement Sensor

4.7 / 5.0 (Verified Fit)

Direct-fit replacement assembly engineered to OEM tolerances for Acura MDX.

$45 – $95 Prime
Check Fitment on Amazon
Sensor Signal Voltage Meter

AstroAI Auto-Ranging Digital Multimeter

4.6 / 5.0 (Best Seller)

Essential for testing 0.1V–5.0V sensor reference signals, ground continuity (<0.20Ω), and harness resistance.

$29.99 Prime
View on Amazon
Top Mobile OBD-II Scanner

BlueDriver Bluetooth Pro OBDII Scan Tool

4.7 / 5.0 (50,000+ Reviews)

Reads and clears enhanced codes (ABS, Airbag, Transmission, Engine) & live freeze-frame telemetry on phone.

Compare OEM & Aftermarket Replacement Sensors for Acura MDXVerified direct-fit pricing from Denso, Bosch, Motorcraft, and ACDelco on Amazon.
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Other Common Fault Codes on Acura MDX

Frequently diagnosed powertrain, emissions, and sensor trouble codes logged on the Acura MDX:

4. Acura MDX P2187 FAQs

What causes code P2187 to trigger on a Acura MDX?

On the Acura MDX (3.5L i-VTEC V6 (290HP) / 3.0L Turbo V6 (Type S 355HP / SH-AWD)), P2187 is most frequently caused by Torn diaphragm in PCV valve / oil separator (common on VW/Audi 2.0T) or Intake manifold gasket or vacuum hose leak.

Where is the OBD-II port located on my Acura MDX?

On the Acura MDX, the 16-pin DLC diagnostic connector is located Driver side lower dash assembly. Plug in any standard OBD-II scanner with the ignition in the ON position to read freeze-frame parameters.

Can I safely drive my Acura MDX with code P2187?

Yes, for moderate driving. Fix promptly to prevent unmetered air from causing lean idle misfires. Given that P2187 carries a Medium severity rating, we advise avoiding heavy towing or aggressive throttle inputs until sensor readings are verified.