Pinpoint Test DL: Cylinder Head Temperature (CHT) Sensor: Introduction
This pinpoint test is intended to diagnose the following:
- cylinder head temperature (CHT) sensor (6G004)
- cylinder head temperature 2 (CHT2) sensor (6G004)
- harness circuits: CHT, CHT2, and SIGRTN
- 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. On applications with a CHT2 sensor, the PCM has a single resistor circuit on the CHT2 input. Refer to the table 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 | |
| Temperature | CHT2 Sensor Values | ||
|---|---|---|---|
| °C | °F | Volts | Resistance (K ohms) |
| -40 | -40 | 4.995 | 965.808 |
| -30 | -22 | 4.990 | 512.947 |
| -20 | -4 | 4.969 | 283.651 |
| -10 | 14 | 4.949 | 162.585 |
| 0 | 32 | 4.917 | 96.248 |
| 10 | 50 | 4.870 | 59.173 |
| 20 | 68 | 4.839 | 37.387 |
| 30 | 86 | 4.802 | 24.216 |
| 40 | 104 | 4.707 | 16.043 |
| 50 | 122 | 4.578 | 10.851 |
| 60 | 140 | 4.411 | 7.487 |
| 70 | 158 | 4.202 | 5.269 |
| 80 | 176 | 3.953 | 3.775 |
| 90 | 194 | 3.667 | 2.750 |
| 100 | 212 | 3.354 | 2.038 |
| 110 | 230 | 3.018 | 1.523 |
| 120 | 248 | 2.680 | 1.155 |
| 130 | 266 | 2.350 | 0.8868 |
| 140 | 284 | 2.040 | 0.6893 |
| 150 | 302 | 1.757 | 0.5418 |
| 160 | 320 | 1.504 | 0.4301 |
| 170 | 338 | 1.282 | 0.3449 |
| 180 | 356 | 1.091 | 0.2791 |
| 190 | 374 | 0.928 | 0.2278 |
| 200 | 392 | 0.789 | 0.1875 |
| 210 | 410 | 0.672 | 0.1554 |
| 220 | 428 | 0.574 | 0.1297 |
| 230 | 446 | 0.491 | 0.1090 |
| 240 | 464 | 0.422 | 0.0921 |
| 250 | 482 | 0.363 | 0.0783 |
| Vehicle | Connector | Pin | Circuit |
|---|---|---|---|
| E-Series, Escape/Kuga, F-Series Super Duty 6.8L, Fusion 2.5L, Motorhome/Stripped Chassis/Step Van, Mustang 3.7L |
A | 2 1 |
SIGRTN CHT |
| All other vehicles | B | 2 1 |
SIGRTN CHT |
| Pin | Circuit |
|---|---|
| 2 | SIGRTN (Signal Return) |
| 1 | CHT2 (Cylinder Head Temperature 2) |
Powertrain Control Module (PCM) Connector
For PCM connector views or reference values, refer to Reference Values .
| Vehicle | Connector | Pin | Circuit |
|---|---|---|---|
| E-Series 5.4L | 190-PIN | E15 E64 |
CHT SIGRTN |
| Edge 2.0L, Edge 2.7L, Explorer 2.3L, F-150 2.7L, MKT 2.0L, MKX 2.0L, MKX 2.7L, Taurus 2.0L |
198 PIN | E20 E36 |
SIGRTN CHT2 |
| Escape/Kuga 1.6L, Escape/Kuga 2.0L, Focus GTDI 2.0L, Focus 2.3L, Fusion 1.5L, Fusion 2.0L, MKC, MKZ 2.0L, Mustang 2.3L, Transit Connect 1.6L |
198 PIN | E20 E46 |
SIGRTN CHT2 |
| Escape/Kuga 2.5L, Fusion 2.5L, MKZ 3.7L |
190-PIN | E39 E49 |
CHT SIGRTN |
| Expedition, Explorer GTDI 3.5L, F-150 GTDI 3.5L, Flex GTDI 3.5L, MKS 3.5L, MKT 3.5L, Navigator, Taurus GTDI 3.5L, Transit 3.5L |
198 PIN | E36 E20 |
CHT SIGRTN |
| F-Series Super Duty | 190-PIN | E30 E32 |
CHT SIGRTN |
| Fiesta, Focus 1.0L |
198 PIN | E10 E13 |
SIGRTN CHT2 |
| Focus GDI 2.0L | 154 PIN | E56 E33 |
CHT SIGRTN |
| Transit Connect 2.5L | 198 PIN | E39 B35 |
CHT SIGRTN |
| All other vehicles | 198 PIN | E47 E49 |
CHT SIGRTN |