P1669 OBD Code Definition:
Injector 4 – Circuit Open/Short to Ground
P1669 OBD Code Description:

Possible Symptoms

• Irregular rpm

Possible Causes

• Wiring and/or connections to/from the Valve for Pump Jet
• Valve for Pump Jet

Possible Solutions

• Check wiring and Check / Clean all connections
• Replace the cable-tree to/from all the Valves for Pump Jet
• Replace Valve for Pump Jet (replace them all !)

Tech Notes

• For each Valve the ECU checks the Begin of Injection Period (BIP) via a voltage. That voltage is very small (less than 0.0001A). Each extra resistance in the cable is fatal. So, in case of any doubt, just replace all cables.