A pontiac bonneville code 56

48-56 psi...very common for fuel pumps...may have an access panel under the back seat some of the older buicks and Pontiac did

Instructions on how to change a headlamp bulb are on page 5-56 in the 2003 Pontiac Bonneville Owner's Manual.
If you do not have an Owner's Manual, you can download a PDF version at the link below (direct link)
2003 Pontiac Owner's Manual

Check vacuum lines at the throttle body for leaks if good then take EGR Valve off and clean carbon out with a non-chlornated brake cleaner.Then clear code from computer and if it comes back on check the fuel pressure it should be 48-55 psi with the key on and the engine off.If its not within these specs then the fuel pump is weak and needs to be replaced.

Hello: You need to find out if there are any codes in the engine control module. Go to a parts store ie: Auto Zone, Advance Auto and have the codes read, they normally don' charge. If the code is for the Evap system have them clear the code and see if it comes back.

code 1870 is an automatic transmission code"transaxle component slipping" there is a loss of shaft RPM in the transmission, the input shaft is turning faster then the output shaft have the sensors tested if they test ok then you will need a transmission.....sorry

k, the diagnostic port is located under the dash on the driver's side. Bring the Pontiac to a parts store. They will plug a hand held scan tool into the port and 'read' any codes stored on the car's computer. This is a FREE service. Good luck.

Could easily be a vacuum leak or a faulty throttle posiiton sensor. Is your check engine light on? If so, I would have the engine codes read to pinpoint exact problem locaiton area.

try disconnecting the battery overnight. otherwise..you need a scan tool to read the codes and reset the computer

do you fill the gas tank with the key on?

Try disconnecting the battery for 1/2 hour an then reconnect and drive for 10 miles. It may run rough for this period. This will clear codes from memory.

Since it is a 1996, you probably have high miles on it.
Most cars after 100,000 miles or so are automatically set to have the check engine light come on.

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