2004 Jetta won't start

Discussion in 'Everything Technical' started by 9016VB3, Jun 1, 2017.

  1. 9016VB3

    9016VB3 Well-Known Member

    Nephew's 04 Jetta 2.0 auto. Throws codes p0321 and p2177. 0321 is engine speed sensor
    Engine Speed Sensor (G28): Implausible Signal
    2177 is:
    Bank 1; System Too Lean off Idle

    Engine cranks, won't start. He limped it home a couple days ago after having problems starting. Replaced crank sensor with a non-bosch one he bought. No change. Fuel pump doesn't fire up when the key is turned. Tested pins in the connector for the fuel pump. Only got 9.25V when cranking, not 12. Not 100% sure I was doing this right, but between the power and ground on the pump, multimeter set to 20 ohms, saw no change from 1.0 when testing resistance between them.

    I'm thinking fuel pump relay, since the crank position sensor didn't do anything, and it's only reading 9.something volts when cranking. Thoughts? Coil, plugs, wires replaced last year.
  2. squid

    squid No Bozo's

    Codes after replacing CPS?

    What are your low and HP fuel pressure numbers?
  3. skwerl43

    skwerl43 Member

    Did you check cam sensor? Even though it says engine speed sensor it's not always the crank sensor. Unless the computer is seeing the right numbers it's not gonna energize the relay and that's why you see what you do for voltage. Just a question. Why are you trying to check for resistance on a partially live circuit? Why are you checking for resistance in the first place? What makes you think the pump is bad or the relay bad? You first should check pump fuse, then see what voltage is going into the relay. After that bypass relay see if pump works. Have you checked grounds and wiring harness for broken or chaffed wires?

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