What Does P1619 Mean?
The glow plug or heater relay control circuit has an open circuit or short to ground condition. This prevents the PCM from properly energizing the glow plug system, which is essential for diesel engine cold starts.
Common Causes
35%
Faulty glow plug relay with internal short or open coil
30%
Damaged wiring harness between PCM and relay with chafing or broken wires
20%
Corroded or loose connector terminals at relay or PCM
10%
PCM internal driver circuit failure
5%
Poor ground connection at relay or system ground point
Diagnostic Steps
1
Step 1: Visually inspect glow plug relay and all associated wiring for damage, corrosion, or loose connections
2
Step 2: Check relay coil resistance with multimeter (typically 50-100 ohms) and verify relay operation with direct 12V supply
3
Step 3: Test circuit continuity from PCM connector to relay and check for short to ground with harness disconnected
4
Step 4: Measure voltage at relay control wire with key on, engine off - should show battery voltage or ground signal depending on manufacturer
5
Step 5: If all circuits test good, suspect PCM internal relay driver failure and verify with known-good PCM or manufacturer diagnostic procedures
Estimated Repair Cost
$150 - $800
Parts + labor, varies by vehicle and location
The glow plug or heater relay control circuit has an open circuit or short to ground condition. This prevents the PCM from properly energizing the glow plug system, which is essential for diesel engine cold starts.
The most common cause of P1619 (Glow Plug/Heater Relay Circ. Open/Short to Ground) is: Faulty glow plug relay with internal short or open coil
Typical repair costs for P1619 range from $150 to $800, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle may be difficult or impossible to start in cold weather. Once started, the engine will run normally but may idle rough initially.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1619 to identify the root cause.
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Quick Info
Category
Powertrain
System
Diesel Cold Start System
Difficulty
Type
Manufacturer
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