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P0245 on 2014-2016 Ford Fiesta ST: Causes and Fixes for Turbo Wastegate Solenoid 'A' Low

On a 2014-2016 Fiesta ST, code P0245 is almost always caused by a failed turbocharger wastegate regulating valve solenoid. This is a known issue documented in Ford's Technical Service Bulletin TSB150162. Replacing the solenoid, OEM part number CJ5Z-9K378-A, is the common fix, costing around $50-$100 for the part.

19 minutes to read 2014-2016 Ford Fiesta ST

Most Likely Cause

Faulty Turbocharger Wastegate Regulating Valve Solenoid

Difficulty

2/5

Est. Time

1.1 hrs

DIY Doable?

✅ Yes

Shop Labor

$120 – $300

Parts Price

$50 – $150

⚠️ Drivable, but... — You can drive the vehicle, but it will have significantly reduced engine power (limp mode) and poor acceleration, often limited to wastegate spring pressure of around 4-6 PSI. Avoid heavy acceleration or long trips until the issue is fixed to prevent unnecessary stress on the engine and turbo system.

Key Takeaways

P0245 on a 2014-2016 Fiesta ST almost always points to a bad turbo wastegate solenoid, part number CJ5Z-9K378-A.
Ford has acknowledged this issue in TSB 15-0162, making diagnosis highly certain.
Symptoms are a Check Engine Light and a major loss of power, as the turbo is effectively disabled and boost is limited to ~4-6 PSI.
The fix is typically replacing the solenoid, which is an accessible and affordable part for DIY or professional repair. Using a genuine OEM part is highly recommended.
Always check the wiring harness for chafing/damage and fuse F24 before replacing parts, as these can also cause the code.

P0245 stands for "Turbocharger/Supercharger Wastegate Solenoid 'A' Circuit Low". This means the Powertrain Control Module (PCM), your car's main computer, has detected a voltage signal from the wastegate control solenoid that is lower than the expected range. The wastegate is a valve that controls the turbocharger's speed and boost pressure; this solenoid is what the PCM uses to operate that valve. A 'low' circuit reading typically points to an electrical problem, like a short in the solenoid itself or its wiring. In response, the PCM will often disable the turbocharger to prevent engine damage, resulting in a significant loss of power.

What's Unique About the 2014-2016 Ford Fiesta ST

The 1.6L GTDI (EcoBoost) engine in the Fiesta ST relies on precise turbocharger control for its performance. Ford has explicitly acknowledged a pattern of failure for the wastegate control solenoid on this platform and its platform mates (Escape, Fusion with the same engine). A specific Technical Service Bulletin (TSB 15-0162) was issued that covers the 2014-2016 Fiesta ST, pointing directly to this solenoid as the cause for P0245 and related codes, making diagnosis more straightforward than on many other vehicles.

Symptoms You May Notice

Check Engine Light (MIL) is on
Significant lack of engine power and acceleration
Sluggish performance, car feels 'lazy'
Turbo boost is erratic or disabled, often limited to a maximum of 4-6 PSI
Inability to build boost past wastegate spring pressure

⚠️ Don't Waste Money on the Wrong Fix

Replacing the entire turbocharger assembly when only the external, serviceable wastegate solenoid is faulty.
Replacing the PCM before thoroughly testing the solenoid and its wiring circuit.
Assuming a boost leak is the primary cause, when the lack of boost is a symptom of the PCM disabling the turbo.

Most Likely Causes

Faulty Turbocharger Wastegate Regulating Valve Solenoid 🔴 High Probability This is a known failure point acknowledged by Ford in TSB 15-0162 for the 1.6L GTDI engine. The solenoid can fail internally, causing an electrical short or high resistance. Forum users report that using cheap, non-OEM solenoids often fails to fix the problem or leads to premature failure.
How to confirm: After checking wiring, this is the most likely component. It can be tested with a multimeter for resistance against factory specifications. A scan tool may also be used to command the solenoid and check for a response. The solenoid's coil resistance should be between 3.42 and 4.18 Ω.
Typical fix: Replace the turbocharger wastegate regulating valve solenoid with a genuine OEM part.
Est. part cost: $70-$150
Wiring or Connector Issue 🟡 Medium Probability The wiring harness in the engine bay is exposed to heat and vibration, which can lead to chafing, breaks, or corrosion over time. One owner on fiestastforum.com found the issue was nicked and shorting wiring near the solenoid after a replacement part didn't solve the code.
How to confirm: Visually inspect the wiring harness and connector going to the wastegate solenoid for any signs of damage, corrosion, or loose pins. Use a multimeter to check for proper voltage and ground at the connector with the ignition on.
Typical fix: Repair the damaged section of wiring or clean/replace the connector.
Est. part cost: $5-$50
Blown Fuse ⚪ Low Probability While more documented on other Ford models, a shorted solenoid or wire can blow the fuse that powers the circuit. A user on fiestastforum.com identified fuse F24 as being related to this system.
How to confirm: Check the fuse box for any blown fuses related to the powertrain or emissions components. The owner's manual will have a diagram of the fuse layout. Specifically check fuse F24.
Typical fix: Replace the blown fuse. If it blows again immediately, a short circuit is present and must be found.
Est. part cost: $1-$5

Rare But Worth Checking

Powertrain Control Module (PCM) Fault: This is very rare. A fault in the PCM's internal driver circuit can cause it to send an incorrect signal or falsely report a low voltage condition. This should only be considered after all other possibilities have been exhaustively ruled out.

Diagnosis Steps

Read all diagnostic trouble codes (DTCs) with an OBD-II scanner. Note P0245 and any other related codes like P0299, P0234, or P0246.
Visually inspect the turbocharger wastegate solenoid and its electrical connector for obvious damage, corrosion, or loose connections.
Carefully inspect the wiring harness leading to the solenoid for any signs of chafing, melting, or breaks, especially where it might rub against other engine components. This was the root cause for at least one owner after a solenoid replacement did not fix the issue.
Check fuse F24 in the engine compartment fuse box to ensure it is not blown.
With the ignition on and engine off, use a multimeter to check for reference voltage at the solenoid's electrical connector. A reading significantly below 12V could confirm the 'low circuit' condition.
Test the internal resistance of the solenoid itself using a multimeter. Disconnect the solenoid and measure across the two pins. The reading should be between 3.42 and 4.18 Ohms. An out-of-spec reading (or an open/short circuit) indicates a faulty solenoid.
Per TSB 15-0162, if no obvious damage to vacuum lines or charge air cooler tubes is found, the recommended action is to replace the turbocharger wastegate regulating valve solenoid.
If a new, quality OEM solenoid does not resolve the code, re-investigate the wiring harness for intermittent shorts before suspecting a rare PCM fault.

Parts You'll Likely Need

Turbocharger Wastegate Regulating Valve Solenoid (OEM #CJ5Z-9K378-A (also seen as CJ5Z9K378A). This part may supersede older numbers like BL3Z-9K378-A or AA5Z-9K378-A. The latest revision is CJ5Z-9K378-B.) — This is the most common failure part for code P0245 on this vehicle, as confirmed by Ford's own Technical Service Bulletin TSB 15-0162.
Trusted brands: Motorcraft (OEM), Pierburg, Dorman
OEM price range: $130-$150
Aftermarket price range: $40-$120

Related Codes That Often Appear With This One

P0299 — Turbo/Supercharger Underboost. This code often appears with P0245 because if the wastegate solenoid is not working correctly, the wastegate may not close properly, preventing the turbo from building sufficient boost.
P0234 — Turbo/Supercharger Overboost Condition. This can occur if the solenoid fails in a way that causes the wastegate to remain shut, leading to excessive boost pressure.
P0246 — Turbocharger Wastegate Solenoid 'A' High. This code indicates the opposite electrical fault (high voltage) but points to the same component or circuit. Seeing it can point to an intermittent wiring short or a failing solenoid.

Technical Service Bulletins (TSBs) & Recalls

TSB 15-0162: 1.6L GTDI - Lack of power with MIL Illuminated - DTCS P0234, P0245, P0246 And/Or P0299.

Platform-Specific Known Issues

Ford issued Technical Service Bulletin TSB 15-0162 specifically for 2014-2016 Fiesta ST models (among others with the 1.6L GTDI engine) that exhibit a lack of power with DTCs P0234, P0245, P0246, and/or P0299. The bulletin's service procedure directs technicians to inspect vacuum lines and charge air cooler tubes, and if no damage is found, to replace the turbocharger wastegate regulating valve solenoid.

Mechanic-Grade Diagnostic Values

Turbocharger Wastegate Regulating Valve Solenoid Coil Resistance — expected: 3.42 - 4.18 Ω (Ohms) at 73° F (23° C). Failure: A reading outside this range, or an open/short circuit, indicates a faulty solenoid.
Wastegate Solenoid Connector Voltage (Key On, Engine Off) — expected: ~12V (Battery Voltage). Failure: A voltage reading significantly below 11V confirms a low voltage condition in the circuit, pointing to a wiring issue, fuse, or PCM fault.

Scan Tool Commands That Help

Ford IDS (Integrated Diagnostic Software): Turbocharger Wastegate — This is a bidirectional control that allows a technician to command the wastegate solenoid on and off. It is used to verify if the solenoid is physically working (an audible click should be heard) and if the PCM is capable of controlling it, which helps isolate the problem between the solenoid, wiring, and PCM.

Wiring & Ground Locations

G104 — Left front of the engine compartment.. This is a primary engine compartment ground. A poor connection at this point can cause a variety of electrical issues and incorrect sensor readings for components controlled by the PCM, including the wastegate solenoid. Bad grounds are a known issue on Fiestas.
PCM Ground — On the frame rail below the air box.. This is the direct ground for the Powertrain Control Module. A fault here can cause the PCM to misinterpret sensor data or fail to properly drive actuators like the wastegate solenoid, potentially triggering a 'low circuit' code.
Wastegate Solenoid Connector — On the wastegate solenoid itself, near the turbocharger assembly.. This 2-pin connector is where voltage and resistance tests are performed. The pins can become corroded or the wiring can chafe near the connector due to engine heat and vibration, causing the 'low circuit' fault.

OEM Part Supersession History

CJ5Z-9K378-A → CJ5Z-9K378-B — Standard part revision and improvement by the manufacturer.
Heads up: The parts are interchangeable. CJ5Z-9K378-B is the recommended replacement for a failed CJ5Z-9K378-A.
CJ5Z-9K378-B → SOL-1 (Motorcraft Service Part Number) — This is the Motorcraft service part number which may be packaged differently but is the same OEM component.

Model Year Variations Within This Range

2016: The 2016 model year Fiesta ST introduced a redesigned air intake system and a different ECU strategy. While the P0245 code and its primary cause (the solenoid) remain the same, aftermarket intakes from 2014-2015 models are not directly compatible with the 2016 model. The ECU change was addressed by tuning companies like Cobb.
2014-2015: Fiesta STs produced between September 2012 and December 2014 were part of a safety recall for potential engine overheating due to insufficient coolant circulation, which could lead to a cracked cylinder head. While not directly causing P0245, severe overheating can damage various engine bay components and wiring, making it a relevant factor for older models in this range.

Diagnostic Flowchart

P0245 indicates a 'low circuit' condition in the wastegate solenoid. Start by checking for power and physical integrity, as this 1.6L GTDI engine is prone to solenoid failure per TSB 15-0162.

Open the engine compartment fuse box. Is Fuse F24 blown?

→ Replace Fuse F24. If it blows again immediately, there is a direct short to ground in the wiring harness or an internal short in the solenoid. Proceed to wiring inspection.

Inspect the wastegate solenoid connector and the wiring harness near the turbo. Any signs of chafing, melting, or nicked wires?

→ Repair the damaged wiring section or replace the connector. Fiesta ST owners often find harness damage where it rubs against engine components due to high heat and vibration.

With ignition ON and engine OFF, use a multimeter to check for 12V at the solenoid connector. Is voltage present?

→ There is an open circuit or high resistance between the fuse box and the solenoid. Trace the power wire from Fuse F24 for a break.

Disconnect the solenoid. Measure resistance across the two pins of the solenoid. Is the reading between 3.42 and 4.18 Ω?

→ The solenoid has failed internally. Replace it with a genuine Ford OEM part. Avoid cheap aftermarket solenoids as they frequently fail to resolve the P0245 code on this platform.

Per TSB 15-0162, have you inspected the vacuum lines and charge air cooler (CAC) tubes for leaks or damage?

→ Repair the vacuum lines or CAC tubes. Even if the code is electrical, physical leaks can cause the PCM to disable boost, complicating the diagnosis.

→ If the solenoid resistance is borderline or the issue is intermittent, replace the wastegate regulating valve solenoid as directed by TSB 15-0162. If the code persists with a new OEM part, suspect a rare PCM fault or an intermittent short in the harness.