Car Will Not Start And OBD Code p0420
I just put a scanner on and got a code p0420 ,my problem is the car won't start it cranks but no start ,day before yesterday it started no prob today no go this has happened a few times ,help please
Answer:
Diagnostic Trouble Codes (DTC) P0420 and P0421 indicate that bank 1 catalyst system efficiency is below the acceptable threshold.
Most of the time this code requires cat converter replacement to fix the converter is no longer efficient. This would be the passenger side. This will not cause a no start check for spark and fuel I would suspect a fuel pump or fuel pump relay is causing this no start. Make sure you have crank signal from the crank position sensor and check the fuel inertia shut off switch.
I would check for fuel pressure when it happens. I would lean more towards a fuel pump or fuel pump relay swap the relay with a headlight or AC relay I believe they are the same compare the part number on them.
Make sure the crank sensor reads cranking rpm about 100-150 rpm when cranking also check the wire to the crank sensor they chafe on the AC compressor.
Car wont start when cold
2000 grand marque 130000 miles 302 motor i believe had plugs replaced at dealer they said no bad codes in computer good gas pressure only hard starts when cold when engine warm runs fine.
Answer:
Your 2000 Grand Marquis has a 4.6L V8. But that's OK.
It sounds like you have a fuel pump problem on cold start.
One way to verify that this is the problem, in the morning when the engine is cold, turn the key to on, NOT START, just on. Leave it there for 3 seconds then turn it to off and then repeat this process 3 times.
Then try to start the vehicle.
If it starts right up, the problem is the fuel pump.
What is happening, overnight or when the vehicle sits for a period of time to cool down, the fuel is returning to the fuel tank. The fuel pump has a check valve in the pump that keeps the fuel in the fuel lines to the engine for easy starting.
When the check valve goes bad, all the fuel in the fuel lines drains back to the fuel tank. Then you have to crank, or cycle the key in the ignition to resupply the fuel lines to the engine.
The check valve is part of the fuel pump itself and is only available with the complete fuel pump assembly.
You will get no codes and the fuel pressure will still be good with the engine running.
You will have to cycle the key on to off.
The fuel pump will only come on for 3 or4 seconds and then turn off. That is why you will have to cycle the key.
If your Grand Marquis has rear air ride suspension, the noise may be the air pump for the rear air springs.
The fuel smell is from pumping the pedal. On fuel injected vehicles, you do not have to step on the gas pedal to start the vehicle, only on carburettor engines from years ago.
To repair the problem, the fuel pump in the fuel tank will have to be replaced. But if you can live with cycling the key on cold starts, you can put it off till later. It will not cause any other issues or problems.
Only the fuel pump itself will cause this, the check valve is part of the pump.
Like I stated, if you can live with cycling the key 3 times when the engine is cold, then you can wait till later to replace the pump.
Security Light ON and Car wont start'
Chevrolet Blazer 4.3 V6 2001 R/H drive.Security light is ON and car will not start.Please help.
This is a common problem with the Passlock security system...turn on the ignition key and try to crank the engine..than let go of the key and wait for 10 minutes, until the security lamp goes off...when it does, try to crank the engine again...if it doesn't fire up then try the 30 minute reprogram procedure.
Another possibility can be shorted fuse or low battery:
I think you may have a shorted battery...the dome lamps and the door locks are another indication of this. Also, these battery positive cables are known for coming slightly loose and driving the on board computers crazy. Check the cables for tightness, if they're loose you'll need to recharge the battery..if they are tight, you'll need to take the battery out and have it tested...it may very well be defective. If the battery is good and cables are tight, be sure there is no corrosion on the cables or where the negative cable attaches the the engine.
Try the 30 minute relearn, otherwise it may have a Passlock Sensor failure or other anti-theft component failure...which will need to be scanned with a dealer level scan tool. There is no way to bypass this style of alarm system, and the keys are not programmable either...try the procedure below a couple of times..
30 Minute Learn Procedure
Notes
Turn ON the ignition, with the engine OFF.
Attempt to start the engine, then release the key to ON (vehicle will not start).
Observe the SECURITY telltale, after approximately 10 minutes the telltale will turn OFF.
Turn OFF the ignition, and wait 5 seconds .
Repeat steps 1 through 4 two more times for a total of 3 cycles/30 minutes (the vehicle is now ready to relearn the Passlock(TM) Sensor Data Code and/or passwords on the next ignition switch transition from OFF to CRANK). IMPORTANT: The vehicle learns the Passlock(TM) Sensor Data Code and/or password XXXXX the next ignition switch transition from OFF to CRANK. You must turn the ignition OFF before attempting to start the vehicle.
Start the engine (the vehicle has now learned the Passlock(TM) Sensor Data Code and/or password).
With a scan tool, clear any DTCs if needed (history DTCs will self clear after 100 ignition cycles).
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If the relearn isn't working than there is a fault in the Passlock System..see the bullitin below...Now the first step is to get a scan of the BCM (Body Control Module) codes and see if any are related to this failure. If you have access to a voltmeter, we can rule out the ignition switch as a failure, and the starter...incase the security lamp is malfunctioning and correctly indicating a security problem.
| Security System - Lamp ON/No Start/DTC B2960 Set |
| Notes |
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File In Section: 08 - Body and Accessories
Bulletin No.: 01-08-56-001A
Date: June, 2001
Subject:
Security Lamp Illuminated on the IP, Engine Stalls, No Start, DTC B2960
(Security System Sensor Data Incorrect but Valid) Set (Inspect and Repair
Cause of DTC B2960)
Models:
1998-2001 Chevrolet and GMC S/T Pickup and Utility Models
(S10, Sonoma, Blazer, Jimmy)
1998-2001 Oldsmobile Bravada
This bulletin is being revised to add information on inspecting for electrical intermittent conditions and important connector C211 tightening steps. Please discard Corporate Bulletin Number 01-08-56-001 (Section 08 - Body and Accessories).
Condition
Some customers may comment on the following conditions. These symptoms may be intermittent.
| ^ | Security lamp illuminates while driving. The Security lamp may be On or Off.
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| ^ | Security lamp is illuminated.
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| ^ | The engine cranks but will not start and the Security lamp is flashing.
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| ^ | The engine starts then stalls and the Security lamp is flashing.
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Cause
Condition(s) may be due to an incorrect Passlock(TM) sensor voltage (which is intermittent) received by the body control module (BCM) from the Passlock(TM) sensor due to the following conditions. Most intermittent conditions are caused by faulty electrical connections or wiring.
| ^ | A 7 ohm variation in the sensor ground circuit wiring, circuit 1057
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| ^ | A 100 ohm variation in the Passlock(TM) sensor signal wiring circuit, circuit 1836
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Inspect for the following items:
| ^ | Broken wiring inside the insulation.
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| ^ | A poor connection between the male and female terminal at a connector. Refer to Testing for Proper Terminal Contact under Testing for Intermittent and Poor Connections in Wiring Systems for the specific procedure.
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| ^ | A poor terminal to wire connection. Some conditions that fall under this description include poor crimps, poor solder joints, crimping over the wire insulation instead of the wire itself, and corrosion in the wire to terminal contact area.
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| ^ | Wire insulation that is rubbed through. This causes an intermittent short as the bare area touches other wiring or parts of the vehicle.
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| ^ | A poor connection between the male and female terminal at a connector. This poor connection may be the result of contamination or deformation.
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| ^ | Contamination may be caused by the connector halves being improperly connected. A missing or damaged connector seal, damage to the connector itself, or exposing the terminals to moisture and dirt can also cause contamination. Contamination, usually in the underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit.
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| - | Separate the connector halves.
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| - | Visually inspect the connector halves for contamination. Contamination may result in a white or green build-up within the connector body or between terminals. This causes high terminal resistance, intermittent contact, or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety including the terminals, the seals, and the connector body.
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| ^ | Deformation is caused by probing the mating surface of a connector terminal without the proper adapter, improperly joining the connector halves. or repeatedly separating and joining the connector halves. Deformation. usually to the female terminal contact tang, can result in poor terminal contact causing an open or intermittently open circuit. Using an equivalent male terminal from the J 38125-B, test that the retention force is significantly different between a good terminal and a suspect terminal. Replace the female terminal in question. |
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Have any of the following components had service recently?
| ^ | The BCM
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| ^ | The ignition lock cylinder case assembly
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| ^ | The PCM/VCM
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If any of the above components have been replaced, the Passlock(TM) Reprogramming Seed and Key (10 Minute Re-Learn) procedure must be performed before any diagnostic procedures are performed. To assist in diagnosis. the following steps are provided.
| 1. | Does the engine crank but not start? If yes, use the Engine Cranks but Does Not Run diagnostic information in the Engine Controls sub-section of the applicable Service Manual.
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| 2. | Observe the security indicator lamp in the top right corner of the instrument panel when you turn the key to the RUN position. Does the indicator lamp show any of the following conditions?
| ^ | Lamp is On for 5 seconds, then goes Off. This is normal operation. The engine should start and run.
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| ^ | Lamp is On and does not go Off. A problem is detected but the engine starts. This indicates that the fault occurred when the engine was running.
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| ^ | Lamp does not come On. This is abnormal operation. Use the Security Indicator Inoperative diagnostic in the Theft Deterrent sub-section of the applicable Service Manual.
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| ^ | Lamp flashes On and Off. This indicates a problem has been detected this key cycle by the Passlock(TM) system and the engine may not start.
No reason to get rid of it over this, might be a little difficult to narrow down without a dealer level scan tool..but we make some tests with a voltmeter. below is the fuse box layouts and antitheft wiring schematic.
Security Indicator: If it is always on, may indicate a faulty alarm module or might just be a glitch...
Fuses:
Do you have access to a voltmeter? I'd like to make a test at the starter and be sure how much voltage we're getting on the remote line...
If the security light has gone out...that means the immobilizer system should be inactive.. the two wiring schematics above are for the immobilizer and starter..but the immobilizer is part of the computer ciruit and you would need a GM level scan tool to see if it is really interfering with the starting...
Does the engine crank over now?
Do you have access to a voltmeter?
below is the underhood fuse box components...it's unusual for the system to act this way after the battery going flat, now there may be a bad Passlock Sensor or the BCM (Body Control Module) which uses the Passlock Sensor signal...if you could scan the BCM codes, we would not for sure what's going on here. With the enigne starting and dying, it further entails a security failure. I would keep trying the 30 minute learn...i've had to try them for hours before, and than it would take..
engine turns over with no compression/ will not start.
i have a 4.6 overhead cam . turns over but sounds like it has no compression. will not start. took lefthand valve cover off and timing chain is not broken. have not removed the right cover as of yet.need to know how to complete the cover removal and how to check the timing , did it jump time?if so , how do i fix it?
Answer:
In some cases, the fast engine turning could be due to an abundance of fuel present. Every time in my experience that a 4.6L V8 spun fast like that, I was able to start it by putting the accelerator to the floor and cranking it for 10-15 seconds at a time. Doing this cranks the engine while shutting fuel pressure off. The only thing you have to be aware of is that you need to allow the starter to cool and make sure the battery is fully charged.
This will help.
Thanks.
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