Question about 2002 Chevrolet TrailBlazer
I have a check eng. light in spring & summer only when outside air temp. is above 70-75 deg. It happens when the cruse is on. The light comes on and the cruse kicks off and will not reset. The trouble code is P1484. Got any ideas. Woody
P1484 - Cooling Fan System Performance
06-06-2005, 10:51 PMHere's what the GM Manual says about this code:
The cooling fan relay sends a pulse width modulation (PWM) signal of 12-14 volts to the cooling fan clutch through the cooling fan clutch supply voltage circuit. The powertrain control module (PCM) uses this PWM signal in order to control the speed of the cooling fan clutch. The signal controls the position of the oil control valve inside the cooling fan clutch. If the cooling fan RPM is different than the PCM is expecting, DTC P1484 will set. The actual cooling fan RPM vs the desired cooling fan RPM is not always exactly the same. There can be up to an 800-RPM difference.
The engine is running.
The system voltage is greater than 8.5 volts.
The intake air temperature (IAT) is greater than -7°C (19°F).
DTCs P1481 and P1482 are not set.
The engine speed is less than 3200 RPM.
The engine speed is not changing more than 250 RPM for 5 seconds.
Fan command is greater than 0%.
The maximum allowable error of 1000 RPM in the cooling fan speed occurs for 100 seconds.
The PCM detects that the cooling fan clutch is locked up.
The Reduced Engine Power indicator illuminates only if the PCM detects that the cooling fan clutch is locked up.
The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed.
The PCM will store the conditions as Freeze Frame/Failure Records data.
The PCM commands the cooling fan clutch to 100%.
Follow this procedure in order to clear DTC P1484 after completing a repair.
Use the Clear DTC Information function on the scan tool.
Perform an ignition key cycle.
The PCM turns OFF the MIL after the third consecutive trip that the diagnostic test has run and passed.
The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
An inline connector could cause an intermittent DTC. Ensure to test for poor connections and pin retention at all inline connectors. Refer to system schematics for connector and locations.
If the condition is not present, refer to Testing for Intermittent and Poor Connections in Wiring Systems.
Disconnect the harness connector of the cooling fan clutch from the shroud. Inspect the exposed wires between the harness connector and the tubing.
If DTCs P1484 and P0113 are set, and the weather conditions are cold, the cooling fan code may be false. Clear DTC P1484, and after an IAT sensor check, allow the DTC to reset .
I'd say that 'fan clutch is faulty' is your problem, based on the information you gave. Thank you for using Fixya and good luck
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Posted on Jan 02, 2017
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