DEF Injector Replacement

Some 2016-2019 Chevrolet Low-Cab Forward (LCF) trucks equipped with the 3.0L diesel engine (RPO IZ3) or 5.2L diesel engine (RPO I1B) may have an illuminated Check Engine MIL and DTC P208E (DEF Injector) set in the Diesel Exhaust Fluid (DEF) control module.

Follow the appropriate Service Information diagnostics for DTC P208E. The DEF control module detects DEF injector sticking by monitoring current change when commanded on. An expected current change should be detected when the interval valve is operated. DTC P208E will set when the DEF control module detects that the current change is small when the DEF injector is commanded on longer than 120 seconds, which indicates a stuck DEF injector.


Return DEF Injector and DEF Supply Pump Filter Element

If diagnostics lead to replacing the DEF injector (Fig. 14), replace the DEF supply pump filter element as well as the DEF injector.


Fig. 14


The DEF supply pump filter element is contained in the DEF supply pump on the chassis. Remove the filter cover (Fig. 15, #2) to access the filter kit. (Fig. 15, #1) Place the supply pump filter element in a bag to be returned with the DEF injector.


Fig. 15


DEF Injector

The DEF injector is attached to the mixer chamber located between the Diesel Particulate Filter (DPF) housing and the Selective Catalytic Reduction (SCR) housing.

When removing the DEF injector, do not disassemble the DEF injector by removing the two central bolts on the injector. (Fig. 16, #1) Disconnect the injector by removing the three nuts on the outer edges of the injector. (Fig. 16, #2) If the two bolts are removed instead, the resin portion may be damaged and the sealing performance may be lost, resulting in an exhaust gas leak. Also, do not reuse the gasket.


Fig. 16


During installation, use a clean cloth to wipe off any foreign matter attached to the DEF injector. Using air to blow off any foreign matter may cause it to enter in the urea passage, resulting in a failure.

Once the DEF injector has been installed, perform the DEF injector data reset procedure for the DEF control module using SPS.

Refer to #PIP5662 for additional information.


– Thanks to Richard Renshaw

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One Comment

  1. i’m having an issue with an injector I installed, I reset the data and now the new one won’t work is there a relearn procedure for it ?