What Does P26A2 Mean?
The voltage in the aftertreatment glow plug circuit is reading higher than expected parameters. This can indicate a wiring short to voltage or a control module failure sending excessive voltage.
Common Causes
40%
Wiring harness shorted to voltage source (battery or ignition power)
30%
Failed glow plug control module with stuck-on relay or driver
15%
Damaged glow plug with internal short causing feedback voltage
10%
Chafed wiring rubbing against hot exhaust components
5%
Water intrusion in connector causing cross-circuit voltage bleed
Diagnostic Steps
1
Step 1: Disconnect glow plug connector and measure voltage at harness side (should be 0V with system off)
2
Step 2: Check for voltage at glow plug connector with ignition on but glow plug not commanded on
3
Step 3: Inspect wiring harness routing near exhaust and other heat sources for damage
4
Step 4: Test glow plug control module operation and check for stuck relay
5
Step 5: Isolate circuit sections to pinpoint location of short to voltage
Estimated Repair Cost
$150 - $800
Parts + labor, varies by vehicle and location
The voltage in the aftertreatment glow plug circuit is reading higher than expected parameters. This can indicate a wiring short to voltage or a control module failure sending excessive voltage.
The most common cause of P26A2 (Exhaust Aftertreatment Glow Plug Circuit High) is: Wiring harness shorted to voltage source (battery or ignition power)
Typical repair costs for P26A2 range from $150 to $800, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Potential fire risk if short circuit is severe. Do not continue driving if burning smell is present. Otherwise, vehicle can be driven cautiously to repair facility.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P26A2 to identify the root cause.
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Quick Info
Category
Powertrain
System
Emissions/Exhaust Aftertreatment
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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