🚨 Diagnostic Profile
Vehicle Make: Dodge
Short Description: The PCM has detected an open or shorted condition in the fuel system relay control circuit. The fuel pump relay control circuit is reading outside its expected electrical range.
Model/Year: Dodge Ram / Charger / Durango / Journey (consistent fuel pump relay control circuit architecture, 2005–2020 range)
Engine: Gasoline V6/V8 (3.6L Pentastar, 5.7L HEMI, or 3.5L/4.7L variants as applicable)
Stored DTC(s): P0691 (Fuel Pump Relay Control Circuit Low) / P0692 (Fuel Pump Relay Control Circuit High)
🚨 Repair Difficulty Tier
Tier: [Intermediate]
Relay replacement itself is straightforward. Isolating an open or short in the control circuit requires multimeter testing, connector inspection, and access to correct wiring information.
🛠️ Resolution Steps
Step 1: Preliminary Inspection
- Verify battery voltage and charging system output (minimum 12.4V key-off, 13.5–14.7V running).
- Locate the fuel system relay: on most Chrysler/Dodge platforms this relay is housed in the Totally Integrated Power Module (TIPM) or Integrated Power Module (IPM) located in the engine bay near the battery; refer to the fuse box lid legend for exact cavity position.
- Inspect the relay, relay socket, and fuse box for corrosion, loose terminals, pushed-out pins, or heat damage.
- Inspect the wiring harness near the relay for chafing, pinched wires, or rodent damage, particularly near the TIPM harness routing and firewall grommet.
- Check for recent aftermarket wiring, accessories, remote starts, or alarm installs tapped into the fuel pump control circuit.
- Review freeze frame data and record key-on and key-off battery voltage.
Step 2: Diagnostic Verification
- Connect scan tool and confirm DTC status (active, pending, or history) along with freeze frame conditions at time of set.
- Command the fuel pump relay on and off with a bidirectional scan tool, if supported, and listen/feel for relay click and confirm pump prime at the tank.
- Measure control circuit voltage at the relay socket with key on: it should toggle between near-0V (relay energized/grounded by PCM driver) and reference battery voltage (relay de-energized), consistent with a low-side driver circuit — a reading that stays fixed high or fixed low indicates an open or short.
- Perform a continuity test on the control circuit (relay socket to PCM connector) with the harness disconnected at both ends to check for an open circuit; resistance should read near 0 ohms (a dead short or infinite reading indicates a fault).
- Check the control circuit for a short to ground or short to voltage by probing the harness with key off and battery disconnected, comparing readings to known-good ground and B+ reference.
- Disconnect the PCM connector only as directed by factory service information and inspect PCM pins for damage, corrosion, or pushed-back terminals — do not probe PCM pins directly with power applied unless specified by the service procedure.
- Refer to factory service information (Mopar/FCA wiring diagrams via AllData, Mitchell1, or TechAuthority) for correct relay control circuit pin-out specific to the exact model/year/engine combination before condemning any component.
Step 3: Resolution & Reset Process
- Repair damaged wiring using solder and heat-shrink or OEM-spec splice connectors, replace corroded terminals, or replace the faulty relay/TIPM as root cause dictates.
- Verify the repair by checking fuel pump operation and fuel pressure against spec (typically 55–65 psi at idle for returnless MPI systems; confirm exact spec in factory service data for the specific engine).
- Clear DTCs with the scan tool and perform a PCM idle relearn/readiness monitor cycle if required.
- Complete a road test covering varied load and idle conditions, and recheck for pending or returning codes.
- Confirm no relay-control circuit faults return after several key cycles and a cold-start test.
📦 Parts, Labor, and Budget Estimates
Required Components/Software:
- Fuel pump relay (OEM Mopar relay, typically interchangeable multi-use relay used across several circuits)
- TIPM/IPM assembly, only if internal relay driver circuit or board trace is confirmed faulty (not a simple relay swap)
- Replacement connector, terminal, or wiring repair kit, if corrosion or chafing is found
- Scan tool with bidirectional control capability (factory-level tool such as Snap-on, Autel, or Chrysler wiTECH preferred for relay command and TIPM diagnostics)
- Digital multimeter with min/max and continuity testing capability
- Factory wiring diagram access (AllData, Mitchell1, or TechAuthority subscription)
Average Component Price:
- Fuel pump relay: $15–$45 (OEM Mopar part)
- TIPM/IPM assembly (only if confirmed faulty, parts only): $300–$650, plus possible dealer programming fee of $100–$200 if module requires VIN-specific flashing
- Connector pigtail or wiring repair materials: $20–$75
- Diagnostic scan software/subscription access (shop tool, amortized): $0–$50 per job if independently billed
Estimated Labor Hours:
0.5–1.0 hour for relay inspection/replacement only; 1.5–2.5 hours total if full circuit diagnosis, wiring repair, or TIPM replacement/programming is required (per standard flat-rate/factory service information guides). Total out-of-pocket estimate ranges from approximately $120–$250 for a straightforward relay/wiring fix, up to $600–$900 if TIPM replacement and dealer programming are necessary.