Fault Detection/Management
WARNING: This page does not describe the selected car, but rather 9 other vehicles, including the 2004 Ford RV Cutaway, 2004 Ford Pickup, 2004 Ford F550 Super Duty, 2004 Ford F450 Super Duty, and 2004 Ford Excursion. However, it is still accessible from the selected car via links, so may be relevant.
The ECT sensor is located on the left side of the front cover. The PCM supplies a five volt reference signal that the ECT sensor uses to produce an analog voltage, indicating temperature. The PCM continuously monitors the signal of the ECT sensor to determine if the signal is within an expected range. If the PCM detects an out of range high or low, the PCM will ignore the ECT signal and substitute the EOT signal. If both ECT and EOT signals are out of range, the PCM will assume an engine coolant temperature of -34°C (-29°F) for starting and 82°C (180°F) for engine running conditions.
CAUTION:
The PCM harness connectors must be properly seated and the connector latch properly attached to eliminate possible driveability concerns or a no start condition. Installing the PCM connectors on an angle may cause an improper connection, misdiagnosis and damaged components. Install the connector until the lever pivots and seats itself. Apply light pressure to get the connector into position on the PCM and then fully seat the connector.
NOTE:
Visually inspect the harness connectors for corrosion, damage, proper mating and correct pin tension.
NOTE:
When the PCM is disconnected additional DTCs will be set. Clear all DTCs after restoring the vehicle.
TEMPERATURE VS. RESISTANCE VALUES (APPROXIMATE)
| °C | °F | OHMS |
|---|---|---|
| 100 | 212 | 177 |
| 90 | 194 | 241 |
| 80 | 176 | 332 |
| 70 | 158 | 467 |
| 60 | 140 | 667 |
| 50 | 122 | 973 |
| 45 | 113 | 1,188 |
| 40 | 104 | 1,459 |
| 35 | 95 | 1,802 |
| 30 | 86 | 2,238 |
| 25 | 77 | 2,796 |
| 20 | 68 | 3,520 |
| 15 | 59 | 4,450 |
| 10 | 50 | 5,670 |
| 5 | 41 | 7,280 |
| 0 | 32 | 9,420 |
| -5 | 23 | 12,300 |
| -10 | 14 | 16,180 |
| -15 | 5 | 21,450 |
| -20 | -4 | 28,680 |
| -30 | -22 | 52,700 |
| -40 | -40 | 100,700 |