🚨 Diagnostic Profile
Vehicle Make: Chrysler
Description: No communication between the Engine Control Module (ECM) and the Injection Pump Module. This fault commonly appears on diesel fuel injection systems (e.g., Cummins-equipped Ram trucks or VM Motori-equipped Jeep/Chrysler diesel applications). Confirm the exact model, year, and engine application before proceeding, as module naming conventions, bus architecture (CAN vs. older J1850), and programming procedures vary significantly between the 5.9L/6.7L Cummins VP44/CP3-based systems and VM Motori CRD platforms.
🚨 Repair Difficulty Tier
Tier: Intermediate
Diagnosis requires network communication testing, power and ground verification, and possible module replacement or reprogramming. Escalate to Professional Only if module replacement requires dealer-level programming (Chrysler wiTECH 2.0 with an active subscription) or if fuel system pressure work is involved on the high-pressure injection pump circuit.
🛠️ Resolution Steps
Step 1: Preliminary Inspection
- Verify battery voltage reads at least 12.4V at rest (key off) and does not drop below 9.6V during cranking; load test or charge the battery if voltage is low, as low system voltage is a common root cause of intermittent module communication faults.
- Inspect ECM and injection pump module connectors for corrosion, spread/backed-out terminals, or moisture intrusion at the engine harness connectors located at the ECM mounting bracket and at the injection pump module housing.
- Inspect the wiring harness for chafing, heat damage, or prior repairs along the routing between the ECM and the injection pump module, paying close attention to areas near the exhaust manifold, turbocharger, and engine mount flex points.
- Check module ground connections for cleanliness, corrosion, and tightness at the engine block-to-chassis ground straps and the ECM case ground, cleaning and re-torquing as needed.
- Review freeze frame data and all stored DTCs (including U-codes indicating network communication loss) before clearing any codes, and document whether the fault is continuous or intermittent.
Step 2: Diagnostic Verification
- Confirm power supply to the injection pump module by checking for battery voltage on the ignition-switched feed circuit with the key in the ON position, engine off.
- Verify ground circuit resistance reads near 0 ohms (under 5 ohms) between the module ground pin and chassis/engine block ground using a digital multimeter.
- Test communication bus integrity with a scan tool capable of Chrysler diesel network diagnostics (wiTECH 2.0 preferred for full module coverage); with the key off and battery disconnected, measure resistance across the CAN High and CAN Low lines at the OBD-II diagnostic connector — a healthy two-resistor terminated network typically measures approximately 60 ohms.
- Check communication lines for shorts to voltage or shorts to ground at the OBD-II connector CAN High/CAN Low circuits and at accessible harness splice points between the ECM and injection pump module.
- Attempt communication with each module individually using the scan tool’s module status screen to determine whether the ECM, the injection pump module, or the shared bus circuit is the source of the no-communication fault.
- Check Chrysler service information (TechAuthority) and applicable Technical Service Bulletins for known network or module faults specific to the confirmed model, year, and engine application.
Step 3: Resolution & Reset Process
- Repair any confirmed harness damage, corroded splices, or connector faults using OEM-style terminals, heat-shrink splices, and dielectric grease per standard wire repair procedures; avoid butt connectors on CAN circuits as they can introduce resistance and signal reflection.
- If a module is confirmed faulty through bus isolation testing, replace it per manufacturer procedure and perform the required module configuration/relearn using Chrysler wiTECH 2.0, including VIN re-sync, security access, and any module-to-module pairing required between the ECM and injection pump module.
- Clear DTCs, perform a full key cycle (OFF for 30+ seconds), and start the engine to confirm stable communication is restored across all modules on the bus.
- Road test the vehicle under varying load and RPM conditions, then recheck with a scan tool for returning U-codes or communication faults before releasing the vehicle.
📦 Parts, Labor, and Budget Estimates
Required Components/Software:
- Injection pump driver module or ECM (only if confirmed faulty through bus isolation testing) — OEM or quality remanufactured unit matched to VIN
- Connector repair kit, OEM-style terminals, heat-shrink splice connectors, and dielectric grease
- Replacement wiring or harness section (engine harness segment), if chafing or heat damage is confirmed
- Chrysler wiTECH 2.0 subscription/programming session for module configuration and relearn
Average Component Price:
- Injection pump driver module: approximately $350–$900 (remanufactured/aftermarket) or $700–$1,400 (OEM dealer)
- ECM/PCM: approximately $450–$1,200 depending on application, plus core charge where applicable
- Connector and wiring repair materials: approximately $20–$150 depending on harness length and connector complexity
- wiTECH programming/configuration fee: approximately $75–$200 per session at an independent shop, or $100–$250 at a dealership
Estimated Labor Hours:
- Diagnosis and verification (bus testing, power/ground checks, module isolation): 1.0–2.0 hours
- Module replacement and programming/configuration: 1.0–2.5 hours
- Wiring or connector repair (variable based on harness accessibility): 0.5–3.0 hours
- Verification and road test: 0.3–0.5 hours
Note: Verify all labor times against the current shop labor guide and all prices against current supplier quotes, as costs vary by region, dealer vs. independent shop, and specific engine/model application.