Case IH Error Code 1000 — What It Means and How to Fix It

Applies to: Magnum 220-340 (Tier 4B), Puma 165-240 (Tier 4B), Steiger 370-620 (Tier 4B)

CIH 1000Case IHManually verified

SCR After-Treatment — DEF/AdBlue System Fault

The selective catalytic reduction (SCR) system has detected a fault. If not resolved, the engine will derate to 60% power after a warning period.

Repair difficulty

Workshop recommended

Repair time

1h 30m

Dealer cost

$600-2800

1
Low or contaminated DEF/AdBlue— Most likely
Refill with fresh ISO 22241-compliant DEF. Old or contaminated DEF breaks down and prevents the SCR system from functioning. If the fluid has turned yellow, drain and refill.
2
Frozen DEF (cold weather)— Possible
DEF freezes at -11°C / 12°F. Most machines have a tank heater that thaws it automatically — allow the machine to idle for 15–20 minutes before working in extreme cold.
3
Failed DEF dosing injector— Possible
The injector that sprays DEF into the exhaust can clog or fail. DEF crystallises in the injector tip during shutdown cycles.
4
NOx sensor fault— Less common
Upstream or downstream NOx sensors can fail. The system needs both to verify SCR catalyst efficiency.

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