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Discussion Starter · #1 ·
My wife's 04 is hard to start after resting more than 8 hours, sounds like it is fuel starved, but smells like gas. Replaced cam sensor, coils, fuel pressure regulator and fuel filter. All misfire codes are gone, but still hard to start and "chugs" until warm. Also throwing new codes: 2401,445,037,2257,414,141,031

Anyone had this issue or any thoughts?

15,841 Posts
P2401 - Evaporative Emission System Leak Detection Pump Control Circuit Low

16839/P0455/001109 - Ross-Tech Wiki

P0037 HO2S Heater Control Circuit Low B1S2 OBD-II Trouble Code Technical Description Article by Dale Dale Toalston ASE Certified Technician HO2S Heater Control Circuit Low (Bank 1 Sensor 2) What does that mean? Heated Oxygen sensors (HO2S) are inputs used by the PCM (Powertrain Control Module) to determine oxygen content in the exhaust system. Bank 1, sensor 2 refers to the second sensor back on bank 1. The PCM uses the information gained from the Bank 1,2 HO2S mainly to monitor the efficiency of the catalytic converter. Integral to this sensor is a heater element The PCM controls this heater to warm up the sensor to operating temperature. This allows the engine to enter closed loop faster and reduces emissions on cold startup. The PCM continuously monitors the heater circuits for abnormal voltages or in some cases, even amperages. Depending on the make of vehicle, the Oxygen sensor heater is controlled one of two ways. One way is that the PCM directly controls the voltage feed to the heater either directly or via a HO2S relay and a ground is supplied from the vehicle's common ground. The other way would be a fused 12 volt Battery feed (B+) that feeds 12 volts to the heater element anytime the ignition is on and the control of the heater is done by a driver in the PCM which controls the ground side of the heater circuit. Finding out which one you have is important because the PCM activates the heater under various circumstances. If the PCM detects an abnormally low voltage condition on the heater circuit, P0037 may set. Symptoms Symptoms of a P0037 DTC may include: Malfunction indicator lamp (MIL) illumination There will likely be no other symptoms Causes Potential causes of a P0037 trouble code may include: Bank 1,2 oxygen sensor heater element has failed Physical damage to heated oxygen sensor has occurred Control circuit (or voltage feed, depending on system) is shorted to ground PCM Oxygen sensor heater driver has failed Possible Solutions Do a visual inspection of the Bank 1,2 HO2S and wiring harness. If there is any damage to the sensor or any damage to the wiring, repair/replace as needed. Make sure wiring is routed away from exhaust. If all appears okay, unplug the Bank 1,2 HO2S and verify that there is 12 volts B+ present with the key on engine off, (or ground is present, depending on the system). Verify the heater control (ground) circuit is intact. If so, remove the o2 sensor and inspect for damage. If you have access to resistance specifications you can use a Ohmmeter to perform a resistance test of the heater element. Infinite resistance indicates an open in the heater. Replace the o2 sensor as necessary.

Read more at: P0037 HO2S Heater Control Circuit Low (Bank 1 Sensor 2)
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DTC P2257 AIR pump relay control circuit low

P0414 Volkswagen
P0414 Volkswagen - Secondary Air Injection System Switching Valve 'A' Circuit Shorted
0 P0414 Volkswagen Comments | Add Comment
Possible causes
- Faulty Air Pump inoperative
- Air bypass solenoid harness is open or shorted
- Air bypass solenoid circuit poor electrical connection
Help with Possible causes What does this mean?
When is the code detected?
The DTC P0414 is detected the the AIR vacuum control solenoid circuit not operating as desired by the PCM.
Possible symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
- Engine hesitation
P0414 Volkswagen Description

An air pump is used on the vehicle to lower tail pipe emissions on start-up. The Powertrain Control Module (PCM) grounds the Air pump relay control circuit which energizes the Air pump. The PCM also grounds the Air combination valve vacuum control solenoid circuit, which energizes the Air vacuum control solenoid. Vacuum is then applied to both Air combination valve diaphragms which opens the shut off valves. The PCM enables both circuits simultaneously when Air system operations id desired. When the AIR system is active, then Air pump forces fresh air into the exhaust stream in order to accelerate catalyst operation. The AIR combination valves replace the conventional check valves. When the AIR system is inactive the shut off valves prevent air flow in either direction.

Read more: P0414 Volkswagen Secondary Air Injection System Switching Valve 'A' Circuit Shorted OBDII Engine Light Trouble Code | Engine-Codes.com

16525/P0141/000321 - Oxygen (Lambda) Sensor B1 S2; Heating Circuit: Malfunction

P0031 - Oxygen (A/F) Sensor Heater Control Circuit Low (Bank 1 Sensor 1) OBD-II Trouble Code Technical Description Oxygen (A/F) Sensor Heater Control Circuit Low (Bank 1 Sensor 1) What does that mean? A P0031 DTC (diagnostic trouble code) refers to the O2 sensor (oxygen sensor) located on Bank 1 in front of the catalytic converter. There is also an oxygen sensor behind the converter which is Sensor #2. This O2 sensor #1 may also be refered to as an air/fuel ratio sensor since on some vehicles it is. It detects the amount of oxygen in the exhaust gas compared to the outside air and then vehicle's computer adjusts the air/fuel ratio going into the engine. The sensor is less effective when the exhaust gas temperature is low, so it includes a heater which is activated to help get better readings from the A/F O2 sensor. Essentially this P0031 code means that the resistance of the heater circuit is lower than normal. In most cases, that resistance level must fall below 0.8 A to trigger the DTC code. Note, this code is very similar in nature to P0032, P0051, and P0052 Potential Symptoms Most likely you'll not notice any symptoms other than the MIL (malfunction indicator lamp, a.k.a. the check engine light) will illuminate. Causes A P0031 DTC trouble code may be caused by one or more of the following: A short or open in the heater circuit in the sensor A failed O2 sensor heater Wiring/connectors broken/frayed leading to sensor and/or relay Failed PCM/ECM Possible Solutions To fix a P0031 DTC code, you'll need to do a proper diagnosis. To do that, you'll want to inspect the wiring and connectors leading to the sensor. Also if equipped with a heater relay and fuse, you'll want to check those as well. Use a digital volt ohm meter to: check for 12 volts at the heater circuit feed (hint: unplug the sensor and check at the wiring connector to do this measurement) check the ground circuit for continuity measure the resistance of the heater circuit (done on the sensor itself) measure the resistance and voltage of the wiring Refer to a service manual for the correct specifications (volts, ohms) for your vehicle. On some Toyota vehicles this code is triggered when the resistance of the heater circuit is below 0.8 A. With that said, a common fix for this DTC is to replace the air/fuel (O2 oxygen) sensor #1 on bank 1. Please keep in mind that OEM (original equipment) replacement sensors are recommended (from the dealer). Aftermarket sensors can be less reliable and of poorer quality (not always, but more often).

Read more at: http://www.obd-codes.com/p0031
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15,841 Posts
Looks like:

1. 02 sensors need replaced: both of them
a. heater circuits bad on both (requires replacement): this may explain hard start and the rich condition you are experiencing.

2. problems with evap system
a. electrical issues with pump
b. large leak detected

3. problems secondary injection system
a. electrical issues
b. check/troubleshoot sai components: (e.g. pump, valves, solenoids, relays, etc.)

If you had a vw scanner; you could get more specific trouble codes; that would help you troubleshoot, things more intelligently. Consider the Vgate vs450 from amazon.com or high end factory level tool VCDS from ross tech.

Can you give us a little history your problems and why you replaced, so many parts on the car (what brand, quality and where did you get the parts you replaced)? What was the original issue you were having with the car? Also, please fill out your info: year, model, trans, your location, etc. that way we can help you more intelligently! Thanks! :)
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