What does it mean?
P1687 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Fuel Injector Control Module Driver Stuck On .
Symptoms
- MIL on with a rough running engine, or the engine will not start at all
- Heavy smoke from the exhaust and a strong raw fuel smell
- Engine oil level rising and smelling of fuel as the cylinder floods
- Severe misfire and heavy loss of power
- Long cranking and hard hot starting
- The engine may run on briefly or knock badly at shutdown
Likely causes
- Failed driver transistor inside the fuel injector control module, stuck in conduction
- Injector control wire shorted to ground so the module reads a permanent on-state
- Chafed harness between the module and the injector, rubbing on a bracket or the valve cover
- Coolant, fuel or moisture contamination inside the injector control module or its connector
- Injector with a shorted internal winding dragging the driver stage down
- Poor module power supply or ground causing the output stage to misbehave
- Incorrect or mismatched module calibration after a replacement
How to fix it
- Check the engine oil level and smell it; if it is fuel-diluted, do not continue to operate the engine
- Read live data and injector driver status to identify which channel is reported stuck on
- Disconnect the suspect injector and see whether the fault follows the injector or stays with the module
- Measure the injector control wire for a short to ground with the module unplugged
- Inspect the harness where it passes brackets, the valve cover and any heat source for chafing
- Measure module supply voltage and ground quality under load
- Replace the injector control module if the output stays latched with the harness proven good, then change the engine oil and filter