What Does P208A Mean?
The diesel exhaust fluid (DEF) reductant pump control circuit has an open or short condition. The ECM cannot properly control the pump that supplies DEF to the selective catalytic reduction (SCR) system.
Safety Warning
Vehicle will enter limp mode or experience reduced power. After a countdown period, the vehicle may not restart until repaired. DEF system is required for emissions compliance.
Common Causes
40%
Failed DEF pump motor or internal electrical fault
30%
Open or damaged wiring in DEF pump circuit
20%
Corroded or damaged DEF pump connector
7%
Blown fuse or relay for DEF pump circuit
3%
ECM driver circuit failure
Diagnostic Steps
1
Step 1: Check DEF pump fuse and relay operation; replace if faulty
2
Step 2: Disconnect DEF pump connector and measure pump motor resistance (typically 2-8 ohms)
3
Step 3: Inspect wiring harness and connector for damage, corrosion, or DEF crystallization
4
Step 4: Check for battery voltage at pump connector with key on and pump commanded on
5
Step 5: If electrical tests pass, replace DEF pump assembly and flush DEF lines if contaminated
Estimated Repair Cost
$400 - $1,500
Parts + labor, varies by vehicle and location
The diesel exhaust fluid (DEF) reductant pump control circuit has an open or short condition. The ECM cannot properly control the pump that supplies DEF to the selective catalytic reduction (SCR) system.
The most common cause of P208A (Reductant Pump Control Circuit/Open) is: Failed DEF pump motor or internal electrical fault
Typical repair costs for P208A range from $400 to $1,500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle will enter limp mode or experience reduced power. After a countdown period, the vehicle may not restart until repaired. DEF system is required for emissions compliance.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P208A to identify the root cause.
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Quick Info
Category
Powertrain
System
Selective Catalytic Reduction (SCR) System
Difficulty
Type
Generic (SAE)
Recommended Tools
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