Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Pinpoint Test DL: Cylinder Head Temperature (CHT) Sensor: Introduction
This pinpoint test is intended to diagnose the following:
- CHT sensor (6G004)
- harness circuits: CHT, VREF, and SIGRTN
- powertrain control module (PCM) (12A650)
On applications that do not use an engine coolant temperature (ECT) sensor, the CHT sensor is used to determine the engine coolant temperature. To cover the entire temperature range of both the CHT and ECT sensors, the PCM has a dual switching resistor circuit on the CHT input. A graph showing the temperature switching from the COLD END line to the HOT END line, with increasing temperature and back with decreasing temperature is included. Note the temperature to voltage overlap zone. Within this zone it is possible to have either a COLD END or HOT END voltage at the same temperature. For example, at 90°C (194°F) the voltage could read either 0.60 volt or 3.71 volts. Refer to Fig 1 and CYLINDER HEAD TEMPERATURE SENSOR EXPECTED VALUES for the temperature to voltage expected values.
Voltage values calculated for VREF = 5 volts. These values can vary by 15% due to sensor and VREF variations.
| Temperature | CHT Sensor Values | |||
|---|---|---|---|---|
| °C | °F | Cold End (volts) | Hot End (volts) | Resistance (K ohms) |
| -40 | -40 | 4.89 | - | 965.808 |
| -30 | -22 | 4.81 | - | 513.019 |
| -20 | -4 | 4.67 | - | 283.664 |
| -10 | 14 | 4.45 | - | 162.584 |
| 0 | 32 | 4.14 | - | 96.255 |
| 10 | 50 | 3.73 | - | 59.175 |
| 20 | 68 | 3.26 | - | 37.387 |
| 30 | 86 | 2.74 | - | 24.215 |
| 40 | 104 | 2.23 | - | 16.043 |
| 50 | 122 | 1.76 | - | 10.85 |
| 60 | 140 | 1.36 | - | 7.487 |
| 70 | 158 | 1.04 | - | 5.268 |
| 80 | 176 | 0.79 | 3.99 | 3.775 |
| 85 | 185 | 0.69 | 3.86 | 3.215 |
| 90 | 194 | 0.60 | 3.71 | 2.75 |
| 95 | 203 | 0.53 | 3.56 | 2.361 |
| 100 | 212 | 0.46 | 3.41 | 2.034 |
| 110 | 230 | - | 3.07 | 1.523 |
| 120 | 248 | - | 2.74 | 1.155 |
| 130 | 266 | - | 2.41 | 0.8866 |
| 140 | 284 | - | 2.10 | 0.6891 |
| 150 | 302 | - | 1.81 | 0.5417 |
| 160 | 320 | - | 1.55 | 0.4301 |
| 170 | 338 | - | 1.33 | 0.3449 |
| 180 | 356 | - | 1.13 | 0.2791 |
| 190 | 374 | - | 0.96 | 0.2278 |
| 200 | 392 | - | 0.82 | 0.1875 |
| 210 | 410 | - | 0.70 | 0.155 |
| 220 | 428 | - | 0.60 | 0.130 |
| 230 | 446 | - | 0.51 | 0.109 |
| 240 | 464 | - | 0.44 | 0.092 |
| 250 | 482 | 0.35 | 0.078 | |
| 260 | 500 | 0.33 | 0.067 | |
For PCM connector views or reference values, refer to REFERENCE VALUES .
| Vehicle | Connector | Pin | Circuit |
|---|---|---|---|
| E-Series 4.6L, E-Series 5.4L, Expedition, F-150, Focus, Navigator, Transit Connect |
190-Pin | E63 E64 E15 |
VREF SIGRTN CHT |
| Edge, Flex 4V 3.5L, MKS 3.7L, MKT 3.7L, MKX, Taurus 4V 3.5L |
190-Pin | B29, B64 E58 E41 |
VREF SIGRTN CHT |
| Escape/Mariner, Flex GTDI 3.5L, Fusion 3.0L, Fusion 2.5L, Milan, MKS 3.5L, MKT 3.5L, Taurus GTDI 3.5L |
190-Pin | E35 E49 E39 |
VREF SIGRTN CHT |
| Fusion 3.5L, MKZ |
140 Pin | E57 E58 E41 |
VREF SIGRTN CHT |
| All other vehicles | 170 Pin | E57 E58 E41 |
VREF SIGRTN CHT |
NO RELATED
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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.