What Does This Mean?
The diagnostic trouble code (DTC) P037F is a generic powertrain code that applies to OBD-II equipped vehicles with glow plugs (diesel engine vehicles).
Affected brands include, among others: Ford, Dodge, Mazda, VW, Ram, GMC, and Chevy. Although generic, repair steps may vary depending on the vehicle’s make, model, and engine. This code appears to be more common on Ford vehicles.
Glow plugs and their circuits are responsible for generating heat in the combustion chamber before cold starts. They operate similarly to a stove element and are essential because diesel engines use compression rather than spark plugs to ignite the fuel/air mixture.
The ECM (Engine Control Module) sets the P037F code when it detects an abnormal electrical value in the glow plug circuit. Most of the time, it’s an electrical issue, although some mechanical problems can also influence this circuit.
This code is closely related to codes P037D and P037E.
Severity of Code P037F
The severity of this code is moderate, but it can be severe in certain situations. For example, if you live in a region with very cold temperatures, repeated cold starts with faulty glow plugs can cause internal engine damage.
Symptoms of Code P037F
Here are the signs that may indicate the presence of this code:
- Difficulty starting in cold weather
- Abnormal engine noises during startup
- Poor engine performance
- Engine misfires
- Increased fuel consumption
Possible Causes of Code P037F
Several causes can be at the origin of this problem:
- Broken or damaged wiring harness
- Blown or defective fuse link
- Faulty glow plug
- Problem with the ECM
- Damaged connectors or pins (corrosion, overheating, etc.)
Code P117E AUDI: Oxygen Sensor Problem
Possible Causes
- Faulty oxygen sensor
- Open or shorted oxygen sensor harness
- Poor electrical connection in the oxygen sensor circuit
- Misfiring cylinder
- Air-fuel ratio too rich or too lean
How to Fix Code P117E AUDI?
- Check the possible causes mentioned above.
- Visually inspect the wiring harness and connectors.
- Look for damaged components.
- Check the connector pins: they should not be broken, bent, pushed out, or corroded.
Possible Symptoms
- Check Engine Light on (or Service Engine Soon warning light)
Meaning of Code P117E AUDI
The Engine Control Module (ECM) monitors the oxygen sensor for Bank 4. It sets the OBDII code when the oxygen sensor for Bank 4 does not meet factory specifications.
Troubleshooting Steps
1. Check Technical Service Bulletins (TSBs)
Before any diagnosis, consult your vehicle’s technical service bulletins. A known fix could save you unnecessary time and expense.
2. Necessary Tools
To work on electrical circuits, it is recommended to have the following tools:
- OBD code reader
- Multimeter
- Socket and ratchet set
- Screwdriver set
- Shop rags/towels
- Battery terminal cleaner
- Vehicle service manual
3. Safety Tips
- Let the engine cool down before any intervention
- Block the wheels to prevent any unintended movement
- Wear personal protective equipment (PPE)
4. Diagnosis and Repair
Step 1: Visual Inspection
- Open the hood and check for any burning smell.
- Look for melted wires or damaged fuse boxes.
- Inspect ground connections (corrosion, poor connection).
Step 2: Wiring Harness Inspection
- Follow the glow plug harness and look for damage.
- Check areas where the harness might rub against the engine or other components.
Step 3: Checking Wire Continuity
- If possible, disconnect the glow plug harness and test continuity with a multimeter.
- If this is not possible on your vehicle model, proceed to the next step.
Step 4: Testing Electrical Circuits
- Consult manufacturer specifications for expected voltage values.
- Use a multimeter to test the involved circuits.
Step 5: Testing Glow Plugs
- Disconnect the glow plug harness.
- With a multimeter in voltage mode, place one probe on the positive battery terminal and the other on the tip of each glow plug.
- The voltage should be equal to the battery voltage. A different value indicates a problem with the glow plug.
- Always consult manufacturer information before performing this test.
Conclusion
Codes P037F and P117E indicate problems affecting the glow plug circuit and the oxygen sensor, respectively. Accurate diagnosis and careful inspection are essential to prevent engine damage and ensure its proper operation.
