Pinpoint Test DX: Engine Coolant Temperature (ECT) Sensor: Introduction

2021 Ford Transit-350 XL, 3.5L Eng VIN G, RWDSECTION Introduction
WARNING: This page does not describe the selected car, but rather 26 other vehicles, including the 2020 Lincoln Navigator, 2020 Lincoln Nautilus, 2020 Lincoln MKZ, 2020 Lincoln Corsair, and 2020 Lincoln Continental. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Engine coolant temperature must be greater than 10°C (50°F) to pass the KOEO self-test and greater than 82°C (180°F) to pass the KOER self-test.

This pinpoint test is intended to diagnose the following:

  • ECT sensor (12A648)
  • harness circuits: ECT and SIGRTN
  • powertrain control module (PCM) (12A650)

Voltage values calculated for VREF equals 5 volts. These values may vary by 15% due to sensor and VREF variations.

G13533246Courtesy of FORD MOTOR CO.
TEMPERATURE SENSOR VOLTAGE AND RESISTANCE SPECIFICATIONS

Temperature Temperature Sensor Values
°C °F Resistance (K ohms)
120 248 1.18
110 230 1.55
100 212 2.07
90 194 2.80
80 176 3.84
70 158 5.37
60 140 7.70
50 122 10.97
40 104 16.15
30 86 24.27
20 68 37.30
10 50 58.75
0 32 95.85
-10 14 160.31
Fig 1: Engine Coolant Temperature (ECT) Sensor Connector
G13533247Courtesy of FORD MOTOR CO.

Harness Side

Circuit Pin
ECT (Engine Coolant Temperature) 1
SIGRTN (Signal Return) 2
Fig 2: Powertrain Control Module (PCM) Connector - For PCM Connector Views
G13533248Courtesy of FORD MOTOR CO.

Harness Side

Circuit Pin
ECT (Engine Coolant Temperature) E38
SIGRTN (Signal Return) E13
RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.