Damaged, chafed or corroded wiring to the hydraulic fan solenoid (open circuit or short to earth or voltage); Loose, corroded or damaged connector at the fan solenoid or control module; Faulty hydraulic cooling fan solenoid with open or shorted coil; Blown fuse or fault in the power supply feeding the solenoid circuit; Fault in the hydraulic fan drive or pump assembly affecting the solenoid; Internal fault in the engine control unit driver circuit.

P1499

Open Or Shorted Condition Detected In The Hydraulic Cooling Fan Solenoid Control.

Pontiac
Powertrain
Manufacturer code
Medium severity

How this code is built

P: SystemPowertrain
1: Defined byThe manufacturer
4: AreaAuxiliary emission controls
99: FaultThe specific fault in that area

What it means

P1499 on a Pontiac means the engine control unit has detected an open circuit or short in the control circuit for the hydraulic cooling fan solenoid. The module drives the solenoid to vary fan speed, and it saw a current or voltage reading outside the expected range, so it logged the fault. Whether the fan is hydraulically driven at all depends on the model and engine, so confirm the cooling fan layout for the specific vehicle.

Symptoms

Check engine light on
Engine running hotter than normal or temperature gauge climbing in traffic
Cooling fan running constantly at full speed or not running at all
Air conditioning performing poorly when stationary
Possible reduced engine power or limp-style strategy if overheating is detected

Possible causes

Damaged, chafed or corroded wiring to the hydraulic fan solenoid (open circuit or short to earth or voltage)likely
Loose, corroded or damaged connector at the fan solenoid or control modulelikely
Faulty hydraulic cooling fan solenoid with open or shorted coillikely
Blown fuse or fault in the power supply feeding the solenoid circuitpossible
Fault in the hydraulic fan drive or pump assembly affecting the solenoidpossible
Internal fault in the engine control unit driver circuitrare

How to diagnose

Read the stored codes and freeze frame data, noting engine temperature and load when the fault set, and check for any other cooling or power steering related codes
Check the cooling system coolant level and look for obvious leaks, and check the hydraulic fluid level if the system has its own reservoir or shares one with the power steering
Visually inspect the fan solenoid wiring and connectors for chafing, heat damage, corrosion and poor pin tension
Check the relevant fuses and the power supply to the solenoid circuit against the wiring diagram for the specific model
Measure the solenoid coil resistance and compare it with the manufacturer specification
Test the control wire for continuity and for shorts to earth or voltage with the module disconnected, following the model wiring diagram
Use a scan tool with bidirectional control, if available, to command the fan and watch whether it responds and whether the fault returns
Check the hydraulic fan drive and pump for leaks, noise and correct operation if the circuit tests good

How to fix

Repair or replace damaged wiring and secure it away from heat and moving parts
Clean or replace corroded or damaged connectors and terminals
Replace the hydraulic fan solenoid if its resistance or operation is out of specification
Replace the blown fuse after finding and correcting the cause of the overload
Repair or replace the hydraulic fan drive or pump if it is found faulty
Replace or repair the control unit only after all wiring and the solenoid have been proven good

Can I keep driving?

Medium severity

Short, cautious journeys are possible if the temperature gauge stays normal, but the fan may not be cooling the engine properly. Avoid heavy traffic and long trips, and stop at once if the engine starts to overheat, as that could cause serious engine damage.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.