How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Pontiac Technician
Category: Pontiac
Satisfied Customers: 2378
Experience:  GM Grand Master Technician 2007. 14 years experience.
Type Your Pontiac Question Here...
GM Tech (Cam) is online now
A new question is answered every 9 seconds

P1811 code, p0303 code, p0128 code, and p0420 codes coming

Customer Question

p1811 code, p0303 code, p0128 code, and p0420 codes coming up, shifting ok just some drag on the driving
JA: How old is the transmission? Have you noticed any leaking?
Customer: original transmission 04 131000, no leaking
JA: What is the model of your '04 Pontiac?
Customer: gtp
JA: Are you fixing your GTP yourself? What have you tried so far?
Customer: no was going to have a tech at my shop look at it, I work at a rv dealership
JA: Anything else you want the mechanic to know before I connect you?
Customer: the shifting is fine, just some drag when driving
Submitted: 9 months ago.
Category: Pontiac
Expert:  david craig replied 9 months ago.

P1811 Description With the engine running and an adaptable shift has occurred, the Powertrain Control Module (PCM) detects during the following conditions occurred twice per trip: Condition 1: 1-2 Shift over 0.65 seconds and 1 -2 Shift adaptive reached its limit. Case 2: 2-3 Shift over 0.65 seconds and 2-3 Shift adaptive reached its limit. Case 3: 3-4 Shift over 0.65 seconds and 3-4 Shift adaptive reached its limit.

P0303 Pontiac Description When a misfire occurs, engine speed will fluctuate. If the engine speed fluctuates enough to cause the Crankshaft Position (CKP) sensor signal to vary, the Engine Control Module (ECM) can determine that a misfire is occurring.

P0128 Pontiac Description An Engine Coolant Temperature (ECT) sensor monitors the temperature of the coolant. This input is used by the Powertrain Control Module (PCM) for engine control and as an enabling criteria for some diagnosis. The air flow coming into the engine is accumulated and used to determine if the vehicle has been driven within the conditions that would allow the engine coolant to heat up normally to the thermostat regulating temperature. If the coolant temperature does not increase normally or does not reach the regulating temperature of the thermostat, the diagnostic that use ECT as enabling criteria may not run when expected.

P0420 Pontiac Description In order to maintain a reasonably low emissions of Hydrocarbons (HC), Carbon Monoxide (CO), and Oxides of Nitrogen (NOx), the engine controls system uses a three-way catalytic converter. The catalyst within the converter promotes a chemical reaction which oxidizes the HC and CO present in the exhaust gas. This reaction converts them into harmless water vapor and Carbon Dioxide. The catalyst also reduces NOx, converting it to Nitrogen. The Powertrain Control Module (PCM) monitors this process using Bank 1 HO2S #2. Bank 1 HO2S #2, located in the exhaust stream past the three-way catalytic converter, produces an output signal which indicates the oxygen storage capacity of the catalyst. This determines the catalysts ability to convert exhaust emissions effectively. If the catalyst is functioning correctly, the Bank 1 HO2S #2 signal will be far less active than that produced by Bank 1 HO2S #1.

Expert:  david craig replied 9 months ago.

you need to have the tranny fluid and filter changed and a line pressure test done on the transmission,.you need to replace the thermostat and flush out the coolant system and you need to swap #3 coli pack with another one to see if the misfire follows or not.

Expert:  david craig replied 9 months ago.

are you there?

Expert:  david craig replied 9 months ago.

do you still need assistance?