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P0354 on Toyota Grand Highlander

Ignition Coil D Primary/Secondary Circuit Malfunction

Factory diagnostic protocol and troubleshooting wire for fault code P0354 specifically for the Toyota Grand Highlander (2024–2026, 2.4L Turbo / 2.5L Hybrid / Hybrid MAX 362HP Turbo AWD).

Verified OEM Telemetry & Field Repair Tree
Toyota Grand Highlander2024–2026
Toyota Grand Highlander
SUV2.4L Turbo / 2.5L Hybrid / Hybrid MAX 362HP Turbo AWD
Reliability
Sensor Voltage Ref
0.1V – 5.0V Ref
Grand Highlander SAE Mode $01
ECU Network Bus
500 kbps CAN-FD
ISO 15765-4 Compliant
Drivability Status
Not Recommended
Critical urgency level
Est. Repair Cost
$100 - $350 (DIY: $30 - $90)
Parts & Labor DIY
Check P0354 On Another Toyota Model:
Diagnose P0354 on Specific Grand Highlander Model Year:

1. Symptoms of P0354 on Toyota Grand Highlander

When the Engine Control Module (ECM/PCM) on your Toyota Grand Highlander (2.4L Turbo / 2.5L Hybrid / Hybrid MAX 362HP Turbo AWD) logs fault code P0354, drivers commonly observe:

Flashing CEL on Toyota Grand Highlander (2.4L Turbo / 2.5L Hybrid / Hybrid MAX 362HP Turbo AWD)
Rough running on Toyota Grand Highlander (2.4L Turbo / 2.5L Hybrid / Hybrid MAX 362HP Turbo AWD)
Loss of power on Toyota Grand Highlander (2.4L Turbo / 2.5L Hybrid / Hybrid MAX 362HP Turbo AWD)
P0304 code on Toyota Grand Highlander (2.4L Turbo / 2.5L Hybrid / Hybrid MAX 362HP Turbo AWD)
Toyota Grand Highlander OBD-II Port Location
The 16-pin diagnostic connector is located Driver side lower knee panel above dead pedal. Plug in your scan tool to verify freeze-frame sensor values.

2. Most Likely Causes on Toyota Grand Highlander

Historical warranty claims and technical repair bulletins for Toyota Grand Highlander point to the following failure distribution:

55%
Dead Cylinder 4 ignition coil (Toyota OEM Part)
25%
Wiring damage (Toyota OEM Part)
12%
Corroded connector (Toyota OEM Part)
* Source: Synthesized from NHTSA ODI field repair telemetry and verified OEM Technical Service Bulletin (TSB) repair tree frequency percentiles for Toyota Grand Highlander.

3. Step-by-Step DIY Repair Guide for Toyota Grand Highlander

01
Test Coil with Swap Method

Swap Coil 4 to Cylinder 1. on the Toyota Grand Highlander equipped with 2.4L Turbo / 2.5L Hybrid / Hybrid MAX 362HP Turbo AWD.

Required Tool: 10mm Socket
02
Replace Coil 4

Install new OEM coil pack. on the Toyota Grand Highlander equipped with 2.4L Turbo / 2.5L Hybrid / Hybrid MAX 362HP Turbo AWD.

Required Tool: Socket Set
03
Clear DTCs

Clear memory and road test. on the Toyota Grand Highlander equipped with 2.4L Turbo / 2.5L Hybrid / Hybrid MAX 362HP Turbo AWD.

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

Equipment for Diagnosing Toyota Grand Highlander (P0354)

Prime Fast Delivery & Verified Fitment
OEM Ignition Component

Direct-Fit Laser Iridium Spark Plugs (Set of 4/6)

4.8 / 5.0 (Top Rated)

Pre-gapped iridium spark plugs engineered to restore smooth combustion on Toyota Grand Highlander.

$36 – $68 Prime
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Ignition Service Tool

Magnetic Swivel Spark Plug Socket Set

4.8 / 5.0 (Amazon Choice)

360-degree magnetic swivel socket prevents ceramic plug cracks inside deep engine spark wells.

$16.99 Prime
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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 Toyota Grand HighlanderVerified direct-fit pricing from Denso, Bosch, Motorcraft, and ACDelco on Amazon.
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Other Common Fault Codes on Toyota Grand Highlander

Frequently diagnosed powertrain, emissions, and sensor trouble codes logged on the Toyota Grand Highlander:

4. Toyota Grand Highlander P0354 FAQs

What causes code P0354 to trigger on a Toyota Grand Highlander?

On the Toyota Grand Highlander (2.4L Turbo / 2.5L Hybrid / Hybrid MAX 362HP Turbo AWD), P0354 is most frequently caused by Dead Cylinder 4 ignition coil or Wiring damage.

Where is the OBD-II port located on my Toyota Grand Highlander?

On the Toyota Grand Highlander, the 16-pin DLC diagnostic connector is located Driver side lower knee panel above dead pedal. Plug in any standard OBD-II scanner with the ignition in the ON position to read freeze-frame parameters.

Can I safely drive my Toyota Grand Highlander with code P0354?

No. Cylinder 4 ignition coil has failed. Given that P0354 carries a Critical severity rating, we advise avoiding heavy towing or aggressive throttle inputs until sensor readings are verified.