Failure mode - Ford F-150 3.0L Power Stroke V6 (2018-2021)
DEF heater faults and harness corrosion (P20BA)
Reliability tier: verified - verify before ordering, see /disclosure/
Symptoms
- 'DEF fluid heater malfunction' in FordPass / Service Engine light, P20BA
- root cause is often corrosion in the DEF heater harness/connector wiring rather than the heater element itself
Compare with the other causes of the same sign on this engine: def, dpf and regeneration warnings (2 causes)
Root cause
The DEF tank heater circuit fails two ways: the heater element and - the common case - harness/connector corrosion. Ford TSB MC-10236685 (05.2023) covers 2018-2021 F-150 3.0L diesel: retrieve DTCs, inspect connectors, replace the harness (with a cable tie fix). VOQ: none of the 59 VIN-confirmed diesel complaints names it (the earlier keyword count of 3 had no diesel VIN).
Diagnosis
- TSB MC-10236685 first: inspect the heater harness/connector for corrosion before ordering the heater or tank unit
Fixes
repair/replace the DEF heater harness per TSB MC-10236685 (connector corrosion is the common fault; splice work, no separate catalog part) ()
replace the DEF tank-side heater/module when the element itself tests open ()
- def-heater-module - more than one option: F-150 3.0L Power Stroke DEF Module (Ford HC3Z-5J229-A, 2018-2019), F-150 3.0L Power Stroke DEF Tank Assembly (Ford JL3Z-5J250-A, 2018-2019)
replace the DEF pump/dosing injector when tank-side pressure/dosing codes appear ()
- def-pump-module - more than one option: F-150 3.0L Power Stroke DEF Dosing Injector (Ford JL3Z-5J281-A, 2018-2021), F-150 3.0L Power Stroke DEF Pump / Sender Assembly (Ford HC3Z-5J229-B, 2018-2021)
Prevalence
common
Parts for this repair run about $200-$960: see them next to the other repairs on this engine in repair costs.