Faulty injection pump calibration sensor or solenoid; Damaged or corroded wiring harness to the injection pump; Loose or dirty electrical connector at the pump; Failed ECU driver circuit for the calibration signal; Internal mechanical wear in the injection pump affecting calibration; Poor ground connection for the pump circuit

DTC codes / Chrysler codes / P1218

P1218 · ChryslerInjection Pump Calibration Circuit

Q: What does code P1218 mean?

Injection Pump Calibration Circuit. P1218 on Chrysler vehicles indicates that the Engine Control Unit (ECU) has detected a fault in the injection pump calibration circuit, which is responsible for delivering precise fuel timing and quantity data to the pump. The ECU monitors the electrical integrity and signal plausibility of this circuit and sets the code when the voltage or resistance falls outside the expected range.

P1218 on Chrysler vehicles indicates that the Engine Control Unit (ECU) has detected a fault in the injection pump calibration circuit, which is responsible for delivering precise fuel timing and quantity data to the pump. The ECU monitors the electrical integrity and signal plausibility of this circuit and sets the code when the voltage or resistance falls outside the expected range.

SystemPowertrain

Code typeChrysler specific

SeverityMedium

Fix difficultyProfessional

AreaFuel and air metering (injector circuits)

Symptoms you may notice

Illumination of the Check Engine Light (CEL) with no other noticeable symptoms
Rough idle or stumbling during acceleration
Reduced engine power or limp mode
Hard starting or extended cranking
Poor fuel economy
Black smoke from the exhaust under load

Common causes, most likely first

Faulty injection pump calibration sensor or solenoid
Damaged or corroded wiring harness to the injection pump
Loose or dirty electrical connector at the pump
Failed ECU driver circuit for the calibration signal
Internal mechanical wear in the injection pump affecting calibration
Poor ground connection for the pump circuit

How to diagnose and fix it

Inspect and clean the injection pump electrical connector and terminals
Check the wiring harness for chafing, corrosion, or loose pins and repair as needed
Measure resistance and voltage on the calibration circuit and compare to factory specifications
Test the calibration sensor or solenoid for proper operation and replace if faulty
Verify ECU software is up to date and reflash if required
Perform a fuel system pressure and timing check to rule out mechanical pump issues
Clear the code and road test to confirm the repair

Before you replace the injection pump

A loose or corroded connector at the pump is a frequent cause that mimics a failed pump, so always inspect the plug first.
The code can be set by a weak battery or charging system issue that causes low voltage to the ECU, so check battery health before condemning the pump.
Aftermarket electrical accessories tapped into the pump circuit can introduce noise and trigger P1218, so look for non-factory wiring.
On some Chrysler diesel models, the calibration circuit shares a ground with other sensors, and a bad ground can set this code without any pump fault.
Replacing the injection pump without first verifying the calibration signal with a lab scope often leads to unnecessary expense.

Can I keep driving with P1218?

You can drive the vehicle short distances to a repair shop, but avoid heavy acceleration or towing because the fault may cause poor performance or increased emissions. If the engine enters limp mode or runs roughly, stop driving and seek professional diagnosis.

Tools that help

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Guidance is general and written for Chrysler vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.