This car is driving me crazy.

Once in a while I get "10-PCM - P0171 Fuel Trim System Lean Bank 1" and the check engine light goes on.

And since last week, after a few miles I get "28-TCS - Traction Control System - C1227 LR Excessive Wheel Speed Variation and C1234 LR Wheel Speed Circuit Open or Shorted".

Specially the 28 TCS ones worry me, as I don't have any technology helping me. I reset the DIC and they insist to get back.

Any clues ?

 

Heres the manual pull on the P0171. The first thing I'd try on the TCS issue is to pull the connectors at the hubs and clean them up. It may be dirty connectors

Document ID# 776154
2002 Chevrolet Corvette
DTC P0171 or P0174
Circuit Description

The powertrain control module (PCM) controls the air/fuel metering system in order to provide the best possible combination of driveability, fuel economy, and emission control. Fuel delivery is controlled differently during open and closed loop. During open loop, the PCM determines fuel delivery based on sensor signals without oxygen sensor input. During closed loop, the oxygen sensor inputs are added and used by the PCM to calculate short and long term fuel trim fuel delivery adjustments. If the oxygen sensors indicate a lean condition, fuel trim values will be above 0 percent. If the oxygen sensors indicate a rich condition, fuel trim values will be below 0 percent. Short term fuel trim values change rapidly in response to the heated oxygen sensor (HO2S) voltage signals. Long term fuel trim makes coarse adjustments in order to maintain an air/fuel ratio of 14.7:1. If the PCM detects an excessively lean condition, this DTC will set.
Conditions for Running the DTC

* DTCs P0101, P0103, P0108, P0135, P0137, P0141, P0200, P0300, P0410, P0420, P0430, P0440, P0442, P0443, P0446, P0449, P0506, P0507 or P1441 are not set.
* The engine coolant temperature (ECT) is between 75-115°C (167-239°F).
* The intake air temperature (IAT) is between -20 and +90°C (4-194°F).
* The manifold absolute pressure (MAP) is between 26-90 kPa (3.7-13 psi).
* The vehicle speed is less than 137 km/h (85 mph).
* The engine speed is between 400-3,000 RPM.
* The barometric pressure (BARO) is more than 74 kPa (10.7 psi).
* The mass airflow (MAF) is between 5-90 g/s.
* The fuel level is more than 10 percent.
* The throttle position (TP) is less than 90 percent.

.
Conditions for Setting the DTC

* The average long term fuel trim cell value is above 23 percent.
* All of the above conditions are present for 6 seconds.

Diagnostic Aids

* The system will go lean if an injector is not supplying enough fuel.
* A lean condition could be present during high fuel demand due to a fuel pump that does not pump enough fuel.
* Use a scan tool in order to review the Failure Records . If an intermittent condition is suspected, refer to Intermittent Conditions .

Test Description

The numbers below refer to the step numbers on the diagnostic table.

5. If the conditions were not corrected, refer to Fuel System Diagnosis for a possible fuel problem.
6. If the conditions were not corrected, a worn cam, worn intake or exhaust valves, or other engine mechanical failure may be the problem.

The test involves checking parameters with a scan tool which most of us dont have. However, these might be worth trying:

1. Turn OFF the engine.
2. Visually and physically inspect the following items:

* The vacuum hoses for splits, kinks, and proper connections. Refer to Emission Hose Routing Diagram .
* Ensure that the vehicle has sufficient fuel in the tank. If the fuel pressure is too low this DTC may set. Refer to Fuel System Diagnosis .
* Fuel contamination.

* Turn OFF the engine.
* Check the HO2S for proper installation.
* Ensure that the electrical connectors and the wires are secure and not contacting the exhaust system.
* Check for a short between the signal circuit and the low reference circuit.

1. Operate the engine at idle.
2. Check for any missing, loose, or leaking exhaust components forward of the HO2S.
3. Check for vacuum leaks at the intake manifold, throttle body, and injector O-rings.
4. Check the air induction system and the air intake ducts for leaks.
5. Check the AIR system for leaks, improper air delivery, and for the shut-off valves not closing.
6. Check the crankcase ventilation system for leaks. Refer to Crankcase Ventilation System Inspection/Diagnosis in Engine Mechanical.

 

DeeGee, thanks !

Just got back from the garage (4:15am and I need to go to work at 8:30!!!).

Basically I followed some steps from this post and cleaned the grounds G101, G102, G103 and G104:
http://forums.corvetteforum.com/c5-t...tion-long.html

I also followed your advice about the connectors on the hubs. The left rear connector was partialy loose as the metal clips that holds it on place is broken, so probably it was boucing all around and giving me the 1224 and 1234 codes, as they are related to that wheel.

Regarding the P0171, may it have some relation with my new Vararam that I installed a few weeks ago ?

 

I'd say the connector on the hub is your problem with the TCS codes

Again, I'd say probably on the P0171 I think I've heard of that problem before after VARARAM fit although I'm not an expert. A tune should be able to sort that out I'd say. Maybe ask the question in the tuning section?

Don't go falling asleep at your desk now