What Does This Indicator Mean?
The Chery Yellow Glow Plug Warning Light, typically represented by a coil-shaped symbol on your instrument cluster, indicates a fault within the pre-heating system of your Chery diesel engine. Unlike gasoline engines that use spark plugs, diesel engines rely on high temperatures generated by compression and electric glow plugs to ignite diesel fuel. The Engine Control Module (ECM) continuously monitors the electrical resistance, circuit continuity, and temperature output of the glow plugs and their associated relay module. When the ECM detects an anomaly—such as a resistance out of specification, an open circuit in one of the heating elements, or a voltage drop in the control circuit—it triggers this yellow warning indicator to alert the driver of a compromised combustion subsystem.
Can I Still Drive with This Light On?
Because this indicator carries a yellow severity rating, the mechanical verdict is that you can drive the vehicle for a short distance under restricted conditions, but you should avoid prolonged operation. If the light illuminates before starting, you may experience extended cranking times or difficulty starting the engine, particularly in cold ambient temperatures. If the light illuminates while driving, the ECM may have entered a protective limp mode, reducing engine power to prevent incomplete combustion and potential particulate filter fouling. Continuing to drive indefinitely with a faulty glow plug system can lead to unburned fuel washing down cylinder walls, heavy carbon buildup on the fuel injectors, and accelerated thermal stress on the diesel particulate filter due to failed regeneration cycles.
Common Causes of the Warning
- Burnt-Out Glow Plug Heating Element: Over thousands of thermal cycles, the internal resistance wire inside the glow plug can fracture or degrade, resulting in an open circuit and a complete failure to reach ignition temperatures.
- Glow Plug Control Module Failure: The solid-state relay or intelligent control unit that meters high current to individual glow plugs can experience internal component failure, preventing power delivery despite a healthy ECM command signal.
- High-Resistance Wiring or Corroded Connectors: Due to engine bay moisture and thermal expansion, the electrical harness terminals connecting to the glow plugs can develop high electrical resistance, causing the ECM to flag a circuit fault code.
How to Diagnose and Reset It
Diagnosing the Chery Yellow Glow Plug Warning Light requires a methodical approach starting with an OBD-II diagnostic scan tool capable of reading manufacturer-specific powertrain fault codes (such as P0670 through P0674 series). Once the specific cylinder fault or general control circuit code is isolated, pop the hood and use a digital multimeter set to ohms to test the electrical resistance of each individual glow plug against ground; a reading of zero or infinite resistance confirms a dead plug. Alternatively, measure voltage drop across the glow plug harness during a cold-start sequence to verify that the control module is supplying proper current. After replacing any failed glow plugs, repairing corroded wiring harness terminals, or swapping a faulty relay, clear the Diagnostic Trouble Codes using your OBD-II scanner to successfully reset the warning indicator on your dashboard.