DTC P1238 Fault Code

[Andyvtr]

Hi all,

After 11 years & 94K miles of trouble free motoring, unfortunately I have a DTC fault code P1238 standing. An internet search suggests an injector malfunction (no other DTC codes active or pending). The engine (2AD-FTV 150PS) doesn't lack power nor cause excessive smoke under acceleration, however does idle a little roughly. I'm thinking perhaps the EGR maybe coked-up and could do with a clean before jumping straight to injector replacement. Any ideas or experiences greatly appreciated. Thank you.

[Devon Aygo]

P1238 indicates a faulty injector,

P1238 (Injection malfunction, except open or short in injector circuit):
This DTC will be set if the engine speed fluctuation between each cylinder is large. The ECM monitors changes in the crankshaft rotation speed using the crankshaft position sensor in order to detect improper combustion. The camshaft position sensor also plays a role in determining which cylinder has the problem. The fluctuation counter increments when irregular crankshaft rotation speed variation exceeds the threshold with the engine idling. Therefore, if any one of the cylinders is operating poorly (rough idle), the ECM sets this DTC.

Diagnosis will require a compatible diagnostics computer capable of carrying out in use tests of the injector operations whilst monitoring data output

[Andyvtr]

Update: I didn't seek professional diagnosis to investigate the fault code, I cleared it with a £20 code reader on two further occasions. What I did do was start adding Redex diesel fuel system cleaner regularly. This improved the engine responsiveness, reduced black smoke and the fault code hasn't reoccurred. Result for Redex! 

[Sam tangri]

I have the same code my Landcruiser and have started adding fuel conditioner. Let’s see what happens. Vehicle has no problem at all. Drives beautifully.