P1698 — Cold-Start Fuel Pump Primary Circuit Fault

P1698 — Cold-Start Fuel Pump Primary Circuit Fault. P1698 can interfere with the dedicated cold-start pump circuit and cause hard starting or stalling.

For Ford vehicles

cold start fuel pump primary circuit ethanol brazilian vehicles only

vehicle

Is it safe to drive?

Cold-start reliability reduced P1698 can interfere with the dedicated cold-start pump circuit and cause hard starting or stalling. If the engine stalls or will not restart while cold, stop driving and repair it; otherwise, address the fault promptly.

Typical symptoms

Hard or extended cranking during a cold start
Engine cranks normally but fails to start when cold
Cold-start stumble, hesitation, or immediate engine stall
Cold-start pump may be inaudible or sound intermittent
Check-engine light may illuminate with P1698 stored

Common causes

Open or high-resistance supply wiring to the cold-start fuel pump
Corroded or loose connector terminals in the pump power or ground path
Failed cold-start fuel pump relay or an open relay-control circuit
Blown fuse or missing battery or ignition feed for the pump circuit
Harness damage caused by chafing or pulling near the fuel tank
Cold-start fuel pump with an internal open, short, or abnormal current draw

How to diagnose with an OBD scanner

Confirm P1698 with an OBD scanner Connect an ELM327-based OBD scanner or AIScanAuto, select the vehicle, and read the stored and pending DTC lists. Confirm P1698 and save any freeze-frame data before clearing the code.
Inspect the cold-start pump circuit Examine the cold-start pump relay, fuse, wiring, connectors, and pump-area harness for corrosion, heat damage, chafing, or loose terminals. Keep away from ignition sources and relieve fuel pressure before opening fuel-system connections.
Measure loaded power and ground Using the vehicle wiring diagram, verify supply voltage during a cold-start pump request and measure voltage drop through both the positive and ground paths. Loaded testing is important because continuity alone can miss a resistive connection.
Separate relay and pump faults Verify relay operation and its control command, then test pump current draw against the service specification. An open circuit points toward wiring, connectors, or the relay, while abnormal pump draw indicates a defective pump.
Repair and verify during a cold start Repair the defective wiring, terminal, fuse, relay, or pump as testing indicates. Clear P1698 with the scanner, allow the engine to cold-soak, then repeat the start while monitoring for code return and confirming proper pump operation.

Approximate repair cost

A rough independent-shop range is approximately USD 250-1,100, depending on whether the repair involves wiring or relay work or requires replacing the cold-start fuel pump. These figures are estimates only, not verified quotes, and vary by region, vehicle, labor time, and parts availability.

Common questions

Does P1698 mean ethanol fuel is causing the fault?

No. The ethanol and Brazilian-vehicle wording identifies the calibration on which P1698 is used; it does not mean ethanol fuel created the electrical fault.

Is P1698 always caused by a failed fuel pump?

No. P1698 can result from pump wiring, a poor connector, a missing supply, relay or control failure, or a defective pump. Loaded voltage and current tests are needed to isolate it.

Can the vehicle be driven with P1698 stored?

Use caution. Driving may be possible if cold starting remains reliable, but any stall, hesitation, or failure to restart after key-off should prompt immediate diagnosis and repair.

What should be checked first when P1698 is present?

Record P1698 and its freeze-frame information with an OBD scanner, inspect the cold-start pump circuit, and then perform loaded voltage-drop and pump-current tests under the vehicle's specified conditions.

P1698 — ---

When your scan tool pulls a P1698 code, the engine control unit is telling you that somewhere in the sensor or actuator circuitry, a signal has stepped outside the factory-calibrated operating window. The PCM constantly watches these circuits while the engine is running, comparing real-time readings against expected values. If the numbers don't match up for long enough across consecutive drive cycles, the module logs P1698 and illuminates the check engine lamp. The stored freeze frame snapshot captures exactly what the engine was doing at that moment — engine speed, load, coolant temperature, vehicle speed — and that's the first clue you should follow when you start troubleshooting P1698.

It's worth understanding that P1698 isn't a problem with a single sensor or switch. The code is a flag raised by the control module whenever any circuit it monitors misbehaves badly enough to exceed tolerance thresholds. The affected component could be upstream or downstream in the system, and the fault might be a hard failure (completely broken) or an intermittent one that comes and go. That ambiguity is why P1698 shows up on dozens of different makes and models without pointing to one specific part — your diagnostic approach has to be systematic.

Symptoms of P1698

The check engine light is the most obvious sign that P1698 has set. Beyond that, the actual driving feel depends entirely on which circuit is malfunctioning:

Check Engine Light remains illuminated after the engine starts
Limp-home mode may activate, restricting power output depending on the affected component
Fuel economy can drop noticeably in some vehicle applications
The related system — whether it's emissions equipment, a throttle circuit, or another actuator — runs erratically or stops functioning entirely
In rare cases, no additional symptoms are noticeable until the code is scanned

Common causes of P1698

The root causes behind P1698 are shared across nearly every vehicle platform that uses this code. Starting with the most frequently encountered:

Degraded or loose ground connection at the component or control module
Corrosion, bent pins, or poor seating at the electrical connector
Internal driver fault inside the PCM or body control module
Failed sensor or actuator drawing or supplying incorrect signal voltage
Blown fuse protecting the circuit from overcurrent damage
Broken, chafed, or shorted wiring within the harness

How to diagnose P1698

Working through P1698 methodically prevents unnecessary part replacements. Follow these steps in order:

Plug in your OBD2 scanner and confirm P1698 is an active or pending code. Record the freeze frame data before clearing anything — those engine conditions are the roadmap for your test drive later.
Pull all stored codes from every module. Related trouble codes often expose which specific circuit is actually at fault. Then search for technical service bulletins under your exact make, model, and model year on the manufacturer portal or NHTSA.gov — many P1698 instances have documented factory fixes or calibration updates.
Inspect the wiring harness and connectors tied to the suspected circuit. Look for broken insulation, corroded terminals, stretched wires, or connectors that aren't fully seated. This step alone resolves a large percentage of P1698 cases.
With a multimeter, check reference voltage, ground integrity, and signal continuity at the component harness. Compare your readings to factory specifications if you have access to a repair database.
Perform a wiggle test on the harness while monitoring live data on your scanner. Any signal dropout or spike pinpoints an intermittent wire break.
Clear the code and drive the vehicle through conditions matching the freeze frame snapshot — similar load, speed, and temperature. If P1698 returns, the fault is confirmed and still present.

Repair options and cost for P1698

The price to resolve P1698 swings wide because the problem could be a simple loose terminal or a failed control module. Here are the typical repair scenarios:

Repair wiring or connectors (most common fix): $80–$250
Replace the faulty sensor or actuator: $150–$500
Repair or replace the control module driver: $300–$1,000

Labor rates at independent shops vary by region, but these figures cover both parts and professional installation. Dealership charges tend to land at the higher end, especially for module-level work.

How much does it cost to fix P1698?

Most P1698 repairs fall somewhere between $80 and $1,000 depending on the root cause. The wide range reflects how drastically the required fix can differ between vehicles — a corroded connector cleaned or spliced costs far less than a new actuator or module swap. Spending time on accurate diagnosis before purchasing parts is the single best way to keep your total bill on the low end of the spectrum. Replacing expensive components first because they seem plausible is how repair bills balloon unnecessarily.

Can you drive with P1698?

P1698 carries a short-term driving safety rating. In most cases the vehicle remains operational, though you may notice reduced performance or an auxiliary system (like throttle response or certain emissions controls) acting abnormally. Avoid letting the code sit indefinitely because underlying issues like bad grounds or shorted wiring can cascade into bigger failures. If the car exhibits stalling, hard starting, or warnings affecting brakes and steering, treat P1698 as a priority and address it immediately.